LED tube lamp

ABSTRACT

A light emitting diode (LED) tube lamp includes a lamp tube; a first pin and a second pin coupled to a first end of the lamp tube, and a third pin coupled to a second end of the lamp tube; a first rectifying circuit comprising diodes and connected to the first and second pins, and a second rectifying circuit comprising diodes and connected to the third pin and an output terminal of the first rectifying circuit; a filtering circuit coupled to the two rectifying circuits and the LED module, for filtering the rectified signal to produce a filtered signal; an LED module comprising LEDs for emitting light, the LED module configured to be driven by the rectified signal or the filtered signal; and a driving circuit coupled between the two rectifying circuits and the LED module, and configured to drive the LED module. The LED tube lamp is configured to receive the external driving signal and emit light in each of two power supply arrangements, the two arrangements being respectively that the external driving signal is a low frequency signal input and transmitted through the first and second pins, and that the external driving signal is a low frequency signal input and transmitted through one of the first and second pins and the third pin across the two ends of the lamp tube. The LED tube lamp is configured such that when the received external driving signal is a low frequency signal, the LED tube lamp causes the rectified signal or the filtered signal to be used by the driving circuit for driving the LED module to emit light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of U.S. patentapplication Ser. No. 15/298,272, filed Oct. 20, 2016, the disclosure ofwhich is incorporated in its entirety by reference herein, which is aContinuation application of U.S. patent application Ser. No. 15/066,645,filed on Mar. 10, 2016, the disclosure of which is incorporated in itsentirety by reference herein, which is a Continuation-In-Partapplication of U.S. patent application Ser. No. 14/865,387, filed Sep.25, 2015, the disclosure of which is incorporated in its entiretyherein, which claims priority under 35 U.S.C. 119(e) to Chinese PatentApplications No. CN 201410507660.9 filed on 2014 Sep. 28; CN201410508899.8 filed on 2014 Sep. 28; CN 201410623355.6 filed on 2014Nov. 6; CN 201410734425.5 filed on 2014 Dec. 5; CN 201510075925.7 filedon 2015 Feb. 12; No. CN 201510104823.3 filed on 2015 Mar. 10; CN201510134586.5 filed on 2015 Mar. 26; CN 201510133689.x filed on 2015Mar. 25; CN 201510136796.8 filed on 2015 Mar. 27; CN 201510155807.7filed on 2015 Apr. 3; CN 201510173861.4 filed on 2015 Apr. 14; CN201510193980.6 filed on 2015 Apr. 22; CN 201510372375.5 filed on 2015Jun. 26; CN 201510259151.3 filed on 2015 May 19; CN 201510268927.8 filedon 2015 May 22; CN 201510284720.x filed on 2015 May 29; CN201510338027.6 filed on 2015 Jun. 17; CN 201510315636.x filed on 2015Jun. 10; CN 201510373492.3 filed on 2015 Jun. 26; CN 201510364735.7filed on 2015 Jun. 26; CN 201510378322.4 filed on 2015 Jun. 29; CN201510391910.1 filed on 2015 Jul. 2; CN 201510406595.5 filed on 2015Jul. 10; CN 201510482944.1 filed on 2015 Aug. 7; CN 201510486115.0 filedon 2015 Aug. 8; CN 201510428680.1 filed on 2015 Jul. 20; CN201510483475.5 filed on 2015 Aug. 8; CN 201510555543.4 filed on 2015Sep. 2; CN 201510557717.0 filed on 2015 Sep. 6; CN 201510595173.7 filedon 2015 Sep. 18, the disclosures of which are incorporated herein intheir entirety by reference. This application also claims priority under35 U.S.C. 119(e) to Chinese Patent Applications no.: CN 201510530110.3filed on 2015 Aug. 26; CN 201510499512.1 filed on 2015 Aug. 14; CN201510448220.5 filed on 2015 Jul. 27; CN 201510645134.3 filed on 2015Oct. 8; and CN 201510680883.x filed on 2015 Oct. 20, the disclosures ofwhich are incorporated herein in their entirety by reference.

If any terms in this application conflict with terms used in anyapplication(s) to which this application claims priority, or termsincorporated by reference into this application or the application(s) towhich this application claims priority, a construction based on theterms as used or defined in this application should be applied.

FIELD OF THE INVENTION

The present disclosure relates to illumination devices, and moreparticularly to an LED tube lamp and its components including the lightsources, electronic components, and end caps.

BACKGROUND

LED lighting technology is rapidly developing to replace traditionalincandescent and fluorescent lightings. LED tube lamps are mercury-freein comparison with fluorescent tube lamps that need to be filled withinert gas and mercury. Thus, it is not surprising that LED tube lampsare becoming a highly desired illumination option among differentavailable lighting systems used in homes and workplaces, which used tobe dominated by traditional lighting options such as compact fluorescentlight bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tubelamps include improved durability and longevity and far less energyconsumption; therefore, when taking into account all factors, they wouldtypically be considered as a cost effective lighting option.

Currently, LED tube lamps used to replace traditional fluorescentlighting devices can be primarily categorized into two types. One is forballast-compatible LED tube lamps, e.g., T-LED lamp, which directlyreplace fluorescent tube lamps without rewiring the lighting fixture;and the other one is for ballast-bypass LED tube lamps, which omittraditional ballast on their circuit and directly connect the commercialelectricity to the LED tube lamp. The latter LED tube lamp is suitablefor the new surroundings in fixtures with new driving circuits and LEDtube lamps. The ballast-compatible type LED tube lamp is also known as“Type-A” LED tube lamp, and the ballast-bypass type LED tube lampprovided with a lamp driving circuit is also known as a “Type-B” LEDtube lamp. Compared to the ballast-compatible type LED tube lamp, theballast-bypass type LED tube lamp has better luminous efficacy andlonger life time since the power consumption and the malfunctionconcerns of the ballast can be excluded.

For the ballast-bypass type LED tube lamp, the power supplyconfiguration can be categorized into two types. One is single-end powersupply configuration, which receives the external AC signal merelythrough one side of the LED tube lamp; and the other one is dual-endpower supply configuration, which receives the external AC signalthrough both sides of the LED tube lamp. In order to fulfill the lightemitting requirements of traditional fluorescent lamps, the circuits ofthe traditional fluorescent lamp fixtures are designed and disposed forproviding the AC signal through both ends of the lamp. For the purposeof replacing traditional fluorescent lamps, an LED tube lamp having thedual-end power supply configuration can be popularized much easier sincethe installation is simpler than the single-end power supplyconfiguration.

However, there still are some drawbacks in the dual-end power supplyconfiguration. For example, when an LED tube lamp has an architecturewith dual-end power supply and one end cap thereof is inserted into alamp socket but the other is not, an electric shock situation could takeplace for the user touching the metal or conductive part of the end capwhich has not been inserted into the lamp socket.

In the published application US 2013/0335959, filed on Jun. 15, 2012, asolution of disposing a mechanical structure on the end cap forpreventing electric shock is proposed. In this electric shock protectiondesign, the connection between the external power and the internalcircuit of the tube lamp can be cut off or established by the mechanicalcomponent's interaction/shifting when a user installs the tube lamp, soas to achieve the electric shock protection. However, due to thephysical characteristics of the mechanical components, the mechanicalfatigue may inevitably cause the reliability and durability of theelectric shock protection to be limited.

On the other hand, although the ballast-bypass type and theballast-compatible type LED tube lamps can be configured in the dual-endpower supply configuration, there still are many differentconsiderations in the power supply circuit design. For example, due tothe frequency of the voltage provided from the ballast being much higherthan the voltage directly provided from the commercial electricity/ACmains, the skin effect occurs when the leakage current is generated inthe ballast-compatible type LED tube lamp, and thus the human body wouldnot be harmed by the leakage current. Therefore, since theballast-bypass type LED tube lamp has higher risk of electricshock/hazard, compared to the ballast-compatible type, it is preferredthat the ballast-bypass type LED tube lamp have extremely low leakagecurrent for meeting strict safety requirements.

In the PCT patent application WO2015/066566, filed on Oct. 31, 2014, asolution of utilizing an electronic switch in the power supply circuitfor preventing electric shock is proposed. In this electric shockprotection design, a transistor/switch is disposed in series with theinput rectification stage of the fluorescent lamp replacement and theLED load, and a current flowing through the sense resistor will bedetected for determining whether the fluorescent lamp replacement iscorrectly connected to the ballast. WO2015/066566 addresses the electricshock protection in the ballast-compatible type LED tube lamp, however,it does not address the electric shock problem in the ballast-bypasstype LED tube lamp.

In detail, compared to the power supply (typically an AC powerline orcommercial electricity) for a ballast-bypass type LED tube lamp, thesignal provided by a ballast (especially electronic ballast) hasrelatively high frequency or voltage. Further, for purposes such as oneof driving a filament of a fluorescent lamp, a ballast may have tooutput a relatively high starting voltage for exciting electrons fromthe filament. So the starting voltage from a ballast can be as high as1200 volts. On the other hand, the ballast-bypass type LED tube lamp istypically powered by commercial electricity with frequency as low ase.g. 50 Hz or 60 Hz and voltage as low as or below about 300 volts.Based on the above characteristics difference between power supplies forthe direct replacement type LED tube lamp and the ballast-bypass typeLED tube lamp, the benchmark and behavior for detecting the installationstate is significantly different between the two types of LED tube lamp.For example, since the waveform of the current flowing through the senseresistor may be significantly different between the two types of LEDtube lamp, utilizing the same determination criteria to determinewhether the LED tube lamp is correctly installed is ineffective and willlikely result in incorrect or inaccurate detection results. Thus, if theshock hazard detection of WO2015/066566 is applied to the ballast-bypasstype LED tube lamp, a wrong detection result is relatively likely tooccur, for example, because of the offset of the input voltage/currentthat may occur for lower frequency power signals.

Further, according to the circuit structure of WO2015/066566, a biascircuit is configured for starting the shock hazard detection, in whichthe input terminals of the bias circuit are connected to the ballastoutput at one side of the fixture. Therefore, the bias circuit can forma loop with the ballast and be powered up when one end of the LED tubelamp is installed on the corresponding socket of the fixture. However,since there is only one output in each side of the fixture for providingthe dual-end power so that the loop of the bias circuit cannot beformed, the shock hazard detection circuit of WO2015/066566 cannot beimplemented in most of the ballast-bypass type LED tube lamps.

SUMMARY OF THE INVENTION

It's specially noted that the present disclosure may actually includeone or more inventions claimed currently or not yet claimed, and foravoiding confusion due to unnecessarily distinguishing between thosepossible inventions at the stage of preparing the specification, thepossible plurality of inventions herein may be collectively referred toas “the (present) invention” herein.

Various embodiments are summarized in this section, and are describedwith respect to the “present invention,” which terminology is used todescribe certain presently disclosed embodiments, whether claimed ornot, and is not necessarily an exhaustive description of all possibleembodiments, but rather is merely a summary of certain embodiments.Certain of the embodiments described below as various aspects of the“present invention” can be combined in different manners to form an LEDtube lamp or a portion thereof.

The present disclosure provides a novel LED tube lamp, and aspectsthereof.

According to certain embodiments, a light-emitting diode (LED) tube lampincludes: a lamp tube; two end caps, each having at least one pin andeach coupled to a respective end of the lamp tube, the pins of the twoend caps for receiving an external driving signal; a first rectifyingcircuit, coupled to a pin of one of the two end caps, for rectifying theexternal driving signal to produce a rectified signal; a secondrectifying circuit, coupled to a pin of the other of the two end caps,for simultaneously rectifying the external driving signal with the firstrectifier; a filtering circuit, coupled to the first and the secondrectifying circuits, for filtering the rectified signal to produce afiltered signal; an LED lighting module, coupled to the filteringcircuit, and configured to receive the filtered signal to produce adriving signal, wherein the LED lighting module includes an LED moduleconfigured to receive the driving signal and emit light; and aninstallation detection module, configured to determine whether to cutoff the external driving signal passing through the LED tube lamp,wherein the installation detection module includes a first installationdetection terminal and a second installation detection terminal, thefirst installation detection terminal is coupled to the first and/or thesecond rectifying circuits, the second installation detection terminalis coupled to the filtering circuit, wherein, the installation detectionmodule is configured such that when a current passing through the firstand the second installation detection terminals is bigger than or equalto a specific current value, the installation detection module conductsto make the LED tube lamp operate in a conductive state; and when thecurrent passing through the first and the second installation detectionterminals is smaller than the specific current value, the installationdetection module cuts off to make the LED tube lamp enter in anon-conducting state.

In some embodiments, the installation detection module includes a switchcircuit, a detection pulse generating module, a detection resultlatching circuit, and a detection determining circuit, wherein thedetection determining circuit is coupled to the detection resultlatching circuit, the first and the second installation detectionterminals, and is configured to detect a signal between the first andthe second installation detection terminals to transmit a detectionresult signal to the detection result latching circuit, wherein thedetection pulse generating module is coupled to the detection resultlatching circuit, and is configured to inform the detection resultlatching circuit of a time point for latching the detection result,wherein the detection result latching circuit is coupled to the switchcircuit and latches a detection result according to the detection resultsignal, and further transmits the detection result to the switchcircuit, wherein the switch circuit controls the state betweenconducting or cut off between the first and the second installationdetection terminals according to the detection result.

In some embodiments, the detection pulse generating module includes afirst capacitor, a second capacitor, a first resistor, a secondresistor, a first buffer, an inverter, a diode, and an OR gate, whereinone end of the first resistor is coupled to an input terminal of theinverter, one end of the second resistor is coupled to an input terminalof the first buffer, a cathode of the diode is coupled to the inputterminal of the first buffer and the diode is coupled with the secondresistor in parallel, one ends of the first and the second capacitorsare jointly coupled, the other ends of the first and the secondcapacitors are correspondingly coupled to the input terminal of theinverter and the input terminal of the first buffer, an output terminalof the inverter and an output terminal of the first buffer are coupledto two input terminals of the OR gate, respectively, an output terminalof the OR gate is coupled to the detection result latching circuit.

In some embodiments, when the one end cap of the LED tube lamp inserts alamp socket and the other end cap thereof is electrically coupled to ahuman body or both the end caps insert the lamp socket, and the anotherend of the first resistor is coupled to a driving voltage, the anotherend of the second resistor is coupled to a reference voltage, and ajoint connection node of the first and the second capacitors is coupledto the driving voltage, the driving voltage at the joint connection nodeof the first and the second capacitors is processed to produce an inputpulse signal on the joint connection node, wherein during a high logiclevel of the input pulse signal inputting the joint connection node, theOR gate outputs a first pulse signal at the output terminal thereof forthe detection result latching circuit latching a detection result basedon the detection result signal and the first pulse signal, further, whenthe input terminal of the first buffer receives a low logic level of theinput pulse signal from the output terminal of the OR gate, the firstpulse signal on the output terminal thereof transferring into a lowlogic level signal.

In some embodiments, a width of the input pulse signal received by thejoint connection node is equal to one time period, and the input pulsesignal keeps a low logic level after the time period is over, whereinfrom the time period is over and the joint connection node receiving thehigh logic level of the input pulse signal and then transferring intothe low logic level signal, the output terminal of the inverter has ahigh logic level signal to make the OR gate output a high logic level ofa second pulse signal for the detection result latching circuit latchingthe detection result based on the detection result signal and the secondpulse signal.

In some embodiments, the pulse width of the first or the second pulsesignal is from 10 us to 1 ms.

In some embodiments, from the output terminal of the invertertransferring into the high logic level and when the voltage on the inputterminal of the inverter rises and is equal to the driving voltage or ahigh logic level, the output terminal of the inverter transfers from thehigh logic level into a low logic level to make the OR gate stopoutputting the second pulse signal or become to output a low logiclevel.

In some embodiments, the pulse width of the second pulse signal isdetermined based on the capacitance of the first capacitor and theresistance of the first resistor.

In some embodiments, a time difference between productions of the firstand second pulse signals or an interval with a defined time between bothof them includes as following: the interval=(X+Y)(T/2), wherein Trepresents a cycle of the external driving signal, X is a naturalnumber, and 0<Y<1. In some embodiments, a range for Y is from about0.05-0.95. And further, in some embodiments, a range for Y is from about0.15-0.85.

In some embodiments, the pulse width of the first pulse signal output bythe OR gate is decided by the capacitance of the second capacitor andthe resistance of the second resistor.

In some embodiments, the time difference between the productions of thefirst and the second pulse signals is not equal to multiple times ofhalf one cycle of the external driving signal, and not corresponding toa multiple of 180 degrees phase difference of the external drivingsignal.

In some embodiments, the detection pulse generating module furtherincludes a third capacitor, a third resistor, and a second buffer,wherein a connection node of the third capacitor and the third resistoris coupled to an input terminal of the second buffer, an output terminalof the second buffer is coupled to the joint connection node of thefirst and the second capacitors, the third capacitor and the thirdresistor are coupled in serial between a driving voltage and a referencevoltage, wherein the third capacitor, the third resistor, and the secondbuffer are configured to process the driving voltage to generate aninput pulse signal at the joint connection node, wherein a width of theinput pulse signal is equal to one time period and a low logic level onthe joint connection node is output after the time period being over.

In some embodiments, the time period is determined by the capacitance ofthe third capacitor and the resistance of the third resistor.

In some embodiments, the detection determining circuit is coupled to thefirst installation detection terminal through a switch circuit couplingterminal and the switch circuit and is coupled to the detection resultlatching circuit via a detection result terminal, wherein the detectiondetermining circuit includes a comparator, and a resistor, wherein anegative input terminal of the comparator receives a reference voltage,a positive input terminal thereof is coupled to the switch circuitcoupling terminal and is coupled to the second installation detectionterminal through the resistor, an output terminal of the comparatorincludes the detection result terminal. In some embodiments, when acurrent of the signal between the first and the second installationdetection terminals passes through the resistor and makes a voltage onthe positive input terminal higher than the reference voltage, thecomparator produces a high logic level of the detection result signaland outputs to the detection result terminal, wherein the comparatorgenerates a low logic level of the detection result signal and outputsto the detection result terminal when a current between the first andthe second installation detection terminals passing through the resistoris insufficient to make the voltage on the positive input terminalhigher than the reference voltage.

In some embodiments, the signal between the first and the secondinstallation detection terminals inputs form the first installationdetection terminal and passes through the switch circuit, the switchcircuit coupling terminal, and the detection determining circuit.

In some embodiments, the detection result latching circuit is coupled tothe detection determining circuit via a detection result terminal, tothe switch circuit via a detection result latching terminal, and to thedetection pulse generating module via a pulse signal output terminal,wherein the detection result latching circuit includes a D flip-flop, aresistor, and an OR gate, wherein the D flip-flop has a CLK inputterminal coupled to the detection result terminal, and a D inputterminal coupled to a driving voltage, one end of the resistor iscoupled to a Q output terminal of the D flip-flop and the other endthereof is coupled to a reference voltage, the OR gate has two inputterminals respectively coupled to the pulse signal output terminal andthe Q output terminal of the D flip-flop, and has an output terminalcoupled to the detection result latching terminal. In some embodiments,when the D input terminal of the D flip-flop is coupled to a drivingvoltage and the another end of the resistor is coupled to a referencevoltage, and further when the detection result terminal outputs a lowlogic level of the detection result signal to the CLK input terminal,the D flip-flop outputs a low logic level signal at the Q outputterminal thereof, but the D flip-flop outputs a high logic level signalat the Q output terminal thereof when the detection result terminaloutputs a high logic level of the detection result signal to the CLKinput terminal, wherein when the OR gate receives a pulse signal fromthe pulse signal output terminal or receives a high logic level signalfrom the Q output terminal of the D flip-flop, the OR gate outputs ahigh logic level of the detection result latching signal at thedetection result latching terminal.

In some embodiments, the switch circuit is coupled to the firstinstallation detection terminal, to the detection result latchingcircuit via a detection result latching terminal, and to the detectiondetermining circuit via a switch circuit coupling terminal, the switchcircuit includes a transistor coupled to the first installationdetection terminal, to the detection result latching terminal, and tothe switch circuit coupling terminal.

In some embodiments, when the detection pulse generating module producesa pulse signal, the transistor conducts to allow the detectiondetermining circuit to perform detection for determining the detectionresult latching signal output by the detection result latching circuitat the detection result latching terminal to be high logic level or lowlogic level, and when the detection result latching signal is high logiclevel, the transistor conducts to make the first and the secondinstallation detection terminals conducting, and when the detectionresult latching signal is low logic level, the transistor cuts off tomake the first and the second installation detection terminals cuttingoff.

In some embodiments, the transistor includes a bipolar junctiontransistor being a power transistor, the bipolar junction transistor hasa collector coupled to the first installation detection terminal, a basecoupled to the detection result latching terminal, and an emittercoupled to the switch circuit coupling terminal.

In some embodiments, when the one end cap of the LED tube lamp isinserted into the lamp socket and the another floats or electricallycouples to a human body, the detection determining circuit outputs a lowlogic level of the detection result signal to the detection resultlatching circuit, and then the detection pulse generating module outputsa low logic level signal to the detection result latching circuit tomake the detection result latching circuit output a low logic level of adetection result latching signal to make the switch circuit cutting off,wherein the switch circuit cutting off makes the first and the secondinstallation detection terminals blocking so as to make the LED tubelamp be in a non-conducting state.

In some embodiments, when the two end caps of the LED tube lamp arecorrectly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level of the detection result signal to thedetection result latching circuit to make the detection result latchingcircuit output a high logic level of the detection result latchingsignal to make the switch circuit conducting, wherein the switch circuitconducting makes the first and the second installation detectionterminals conducting so as to make the LED tube lamp operate in aconducting state.

According to some embodiments of the LED tube lamp described herein, theend cap assembly will not conduct before being correctly inserted intothe lamp socket so as to provide a safety protection for the user fromelectric shock.

According to some embodiments, a light-emitting diode (LED) tube lampincludes a lamp tube; two end caps, each having at least one pin, andeach coupled to a respective end of the lamp tube, the pins of the twoend caps for receiving a driving signal; an LED module coupled to thetwo end caps, and configured to emit light in response to the drivingsignal; and an installation detection circuit configured to determinewhether to cut off a current generated from the driving signal fromreaching the LED module, the installation detection circuit having aninput terminal and output terminal. The installation detection circuitmay be configured such that when a current passing through the inputterminal and the output terminal is bigger than or equal to a specificcurrent value, the installation detection circuit conducts to make theLED module operate in a conductive state, and when the current passingthrough the input terminal and output terminal is smaller than thespecific current value, the installation detection circuit cuts off tomake the LED module enter in a non-conducting state.

In some embodiments, the installation detection circuit furthercomprises: a first circuit configured to output two pulse signals, thefirst pulse signal output at a first time and the second pulse signaloutput at a second time after the first time; and a switch configured toreceive the driving signal and to receive the two pulse signals. In someembodiments, the two pulse signals control turning on and off of theswitch to control whether the LED module operates in a conductive stateor in a non-conducting state.

According to some embodiments, the driving signal is an alternatingcurrent (AC) signal having a period; and the amount of time between thefirst time and the second time is not a multiple of half of the periodof the driving signal. For example, the first time may be at thebeginning of the first pulse signal; and the second time may be at thebeginning of the second pulse signal. In some embodiments, a timedifference between productions of the first and second pulse signals oran interval with a defined time between both of them is the following:the interval=(X+Y)(T/2), wherein T represents the period of the drivingsignal, X is a natural number, and 0.05<Y<0.95.

According to some embodiments, the LED tube lamp further includes afirst rectifying circuit connected between the input terminal of theinstallation detection circuit and a first pin of one end cap of the twoend caps; and a filtering circuit connected between the output terminalof the installation detection circuit and the lighting module.

The LED tube lamp may further include a second rectifying circuit,coupled to a first pin of the other of the two end caps and coupled tothe installation detection circuit.

In some embodiments, the LED tube lamp includes a driving circuitcoupled between the LED module and the installation detection circuit.

According to certain embodiments, an LED tube lamp includes aninstallation detection circuit. The installation detection circuitincludes a first circuit configured to output a plurality of pulsesignals including a first pulse signal and a second pulse signal, thefirst pulse signal output at a first time and the second pulse signaloutput at a second time after the first time; and a switch configured toreceive an LED driving signal and to receive the plurality of pulsesignals, wherein the plurality of pulse signals control turning on andoff of the switch. The installation detection circuit is configured to:during a detection stage, detect during each of the plurality of pulsesignals whether the LED tube lamp is properly connected to a lampsocket; when it is not detected during any of the plurality of pulsesignals that the LED tube lamp is properly connected to the lamp socket,control the switch to remain in an off state after the detection stage;and when it is detected during at least one of the plurality of pulsesignals that the LED tube lamp is properly connected to the lamp socket,control the switch to remain in an on state after the detection stage.

In some embodiments, the LED tube lamp further includes a latch circuitconnected to the switch and configured to control turning on and off ofthe switch.

In some embodiments, the LED driving signal is an AC signal having aperiod; and the amount of time between the first time and the secondtime is not a multiple of half of the period of the LED driving signal.For example, the first time may be at the beginning of the first pulsesignal; and the second time may be at the beginning of the second pulsesignal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating an LED tube lampaccording to one embodiment of the present invention;

FIG. 1A is a perspective view schematically illustrating the differentsized end caps of an LED tube lamp according to another embodiment ofthe present invention to illustrate;

FIG. 2 is an exemplary exploded view schematically illustrating the LEDtube lamp shown in FIG. 1;

FIG. 3 is a perspective view schematically illustrating front and top ofan end cap of the LED tube lamp according to one embodiment of thepresent invention;

FIG. 4 is an exemplary perspective view schematically illustratingbottom of the end cap as shown in FIG. 3;

FIG. 5 is a perspective view schematically illustrating still anotherend cap of an LED tube lamp according to still another embodiment of thepresent invention;

FIG. 6 is a plane cross-sectional view schematically illustrating theLED light strip is a bendable circuit sheet with ends thereof passingacross the transition region of the lamp tube of the LED tube lamp to besoldering bonded to the output terminals of the power supply accordingto one embodiment of the present invention;

FIG. 7 is a plane cross-sectional view schematically illustrating abi-layered structure of the bendable circuit sheet of the LED lightstrip of the LED tube lamp according to an embodiment of the presentinvention;

FIG. 8 is a perspective view schematically illustrating the solderingpad of the bendable circuit sheet of the LED light strip for solderingconnection with the printed circuit board of the power supply of the LEDtube lamp according to one embodiment of the present invention;

FIG. 9 is a plane view schematically illustrating the arrangement of thesoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to one embodiment of the present invention;

FIG. 10 is a plane view schematically illustrating a row of threesoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to another embodiment of the presentinvention;

FIG. 11 is a plane view schematically illustrating two rows of solderingpads of the bendable circuit sheet of the LED light strip of the LEDtube lamp according to still another embodiment of the presentinvention;

FIG. 12 is a plane view schematically illustrating a row of foursoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to yet another embodiment of the presentinvention;

FIG. 13 is a plane view schematically illustrating two rows of twosoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to yet still another embodiment of thepresent invention;

FIG. 14 is a plane view schematically illustrating through holes areformed on the soldering pads of the bendable circuit sheet of the LEDlight strip of the LED tube lamp according to one embodiment of thepresent invention;

FIG. 15 is a plane cross-sectional view schematically illustratingsoldering bonding process utilizing the soldering pads of the bendablecircuit sheet of the LED light strip of FIG. 14 taken from side view andthe printed circuit board of the power supply according to oneembodiment of the present invention;

FIG. 16 is a plane cross-sectional view schematically illustratingsoldering bonding process utilizing the soldering pads of the bendablecircuit sheet of the LED light strip of FIG. 14 taken from side view andthe printed circuit board of the power supply according to anotherembodiment of the present invention, wherein the through hole of thesoldering pads is near the edge of the bendable circuit sheet;

FIG. 17 is a plane view schematically illustrating notches formed on thesoldering pads of the bendable circuit sheet of the LED light strip ofthe LED tube lamp according to one embodiment of the present invention;

FIG. 18 is an exemplary plane cross-sectional view of FIG. 17 takenalong a line A-A′;

FIG. 19 is a perspective view schematically illustrating a circuit boardassembly composed of the bendable circuit sheet of the LED light stripand the printed circuit board of the power supply according to anotherembodiment of the present invention;

FIG. 20 is a perspective view schematically illustrating anotherarrangement of the circuit board assembly of FIG. 19;

FIG. 21 is a perspective view schematically illustrating a power supplyof the LED tube lamp according to one embodiment of the presentinvention;

FIG. 22 is a perspective view schematically illustrating the printedcircuit board of the power supply, which is perpendicularly adhered to ahard circuit board made of aluminum via soldering according to anotherembodiment of the present invention;

FIG. 23 is a perspective view schematically illustrating the bendablecircuit sheet of the LED light strip is formed with two conductivewiring layers according to another embodiment of the present invention;

FIG. 24A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 24B is a circuit block diagram of an LED lamp according to someembodiments of the present invention;

FIG. 25A is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 25B is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 25C is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 25D is a schematic diagram of a rectifying circuit according tosome embodiments of the present invention;

FIG. 26A is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 26B is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 26C is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 26D is a schematic diagram of a terminal adapter circuit accordingto some embodiments of the present invention;

FIG. 27A is a block diagram of a filtering circuit according to someembodiments of the present invention;

FIG. 27B is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 27C is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 27D is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 27E is a schematic diagram of a filtering unit according to someembodiments of the present invention;

FIG. 28A is a schematic diagram of an LED module according to someembodiments of the present invention;

FIG. 28B is a schematic diagram of an LED module according to someembodiments of the present invention;

FIG. 28C is a plan view of a circuit layout of the LED module accordingto some embodiments of the present invention;

FIG. 28D is a plan view of a circuit layout of the LED module accordingto some embodiments of the present invention;

FIG. 28E is a plan view of a circuit layout of the LED module accordingto some embodiments of the present invention;

FIG. 29A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 29B is a block diagram of a driving circuit according to someembodiments of the present invention;

FIG. 29C is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 29D is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 29E is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 29F is a schematic diagram of a driving circuit according to someembodiments of the present invention;

FIG. 29G is a block diagram of a driving circuit according to someembodiments of the present invention;

FIG. 29H is a graph illustrating the relationship between the voltageVin and the objective current Iout according to certain embodiments ofthe present invention;

FIG. 30A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 30B is a schematic diagram of an anti-flickering circuit accordingto some embodiments of the present invention;

FIG. 31A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 31B is a schematic diagram of a protection circuit according tosome embodiments of the present invention;

FIG. 32A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 32B is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32C is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32D is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32E is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32F is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32G is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32H is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments of the present invention;

FIG. 32I is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiment of the present invention;

FIG. 33A is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 33B is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 33C illustrates an arrangement with a ballast-compatible circuit inan LED lamp according to some embodiments of the present invention;

FIG. 33D is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 33E is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 33F is a schematic diagram of a ballast-compatible circuitaccording to some embodiments of the present invention;

FIG. 33G is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments of the present invention;

FIG. 33H is a schematic diagram of a ballast-compatible circuitaccording to some embodiments of the present invention;

FIG. 33I illustrates a ballast-compatible circuit according to someembodiments of the present invention;

FIG. 34A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 34B is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 34C is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 34D is a schematic diagram of a ballast-compatible circuitaccording to some embodiments of the present invention;

FIG. 35A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 35B is a schematic diagram of a filament-simulating circuitaccording to some embodiments of the present invention;

FIG. 35C is a schematic block diagram including a filament-simulatingcircuit according to some embodiments of the present invention;

FIG. 35D is a schematic block diagram including a filament-simulatingcircuit according to some embodiments of the present invention;

FIG. 35E is a schematic diagram of a filament-simulating circuitaccording to some embodiments of the present invention;

FIG. 35F is a schematic block diagram including a filament-simulatingcircuit according to some embodiments of the present invention;

FIG. 36A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 36B is a schematic diagram of an OVP circuit according to anembodiment of the present invention;

FIG. 37A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 37B is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 37C is a block diagram of a ballast detection circuit according tosome embodiments of the present invention;

FIG. 37D is a schematic diagram of a ballast detection circuit accordingto some embodiments of the present invention;

FIG. 37E is a schematic diagram of a ballast detection circuit accordingto some embodiments of the present invention;

FIG. 38A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 38B is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 38C is a schematic diagram of an auxiliary power module accordingto an embodiment of the present invention;

FIG. 39A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments of the present invention;

FIG. 39B is a block diagram of an installation detection moduleaccording to some embodiments of the present invention;

FIG. 39C is a schematic detection pulse generating module according tosome embodiments of the present invention;

FIG. 39D is a schematic detection determining circuit according to someembodiments of the present invention;

FIG. 39E is a schematic detection result latching circuit according tosome embodiments of the present invention;

FIG. 39F is a schematic switch circuit according to some embodiments ofthe present invention;

FIGS. 40A-F are several structures of end caps according to someembodiments of the present invention;

FIG. 41 is a schematic structure of an LED tube lamp according to someembodiments of the present invention;

FIG. 42 is an alternative micro switch embodiment of FIG. 41; and

FIG. 43 is a circuit diagram of an LED lamp according to someembodiments.

DETAILED DESCRIPTION

The present disclosure provides a novel LED tube lamp. The presentdisclosure will now be described in the following embodiments withreference to the drawings. The following descriptions of variousembodiments of this invention are presented herein for purpose ofillustration and giving examples only. It is not intended to beexhaustive or to be limited to the precise form disclosed. These exampleembodiments are just that—examples—and many implementations andvariations are possible that do not require the details provided herein.It should also be emphasized that the disclosure provides details ofalternative examples, but such listing of alternatives is notexhaustive. Furthermore, any consistency of detail between variousexamples should not be interpreted as requiring such detail—it isimpracticable to list every possible variation for every featuredescribed herein. The language of the claims should be referenced indetermining the requirements of the invention.

In the drawings, the size and relative sizes of components may beexaggerated for clarity. Like numbers refer to like elements throughout.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, or steps, these elements, components, regions, layers, and/orsteps should not be limited by these terms. Unless the context indicatesotherwise, these terms are only used to distinguish one element,component, region, layer, or step from another element, component,region, or step, for example as a naming convention. Thus, a firstelement, component, region, layer, or step discussed below in onesection of the specification could be termed a second element,component, region, layer, or step in another section of thespecification or in the claims without departing from the teachings ofthe present invention. In addition, in certain cases, even if a term isnot described using “first,” “second,” etc., in the specification, itmay still be referred to as “first” or “second” in a claim in order todistinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to or “on” another element, it can be directlyconnected or coupled to or on the other element or intervening elementsmay be present. In contrast, when an element is referred to as being“directly connected” or “directly coupled” to another element, there areno intervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). However, the term “contact,” as used herein refers todirect contact (i.e., touching) unless the context indicates otherwise.

Embodiments described herein will be described referring to plane viewsand/or cross-sectional views by way of ideal schematic views.Accordingly, the exemplary views may be modified depending onmanufacturing technologies and/or tolerances. Therefore, the disclosedembodiments are not limited to those shown in the views, but includemodifications in configuration formed on the basis of manufacturingprocesses. Therefore, regions exemplified in figures may have schematicproperties, and shapes of regions shown in figures may exemplifyspecific shapes of regions of elements to which aspects of the inventionare not limited.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Terms such as “same,” “equal,” “planar,” or “coplanar,” as used hereinwhen referring to orientation, layout, location, shapes, sizes, amounts,or other measures do not necessarily mean an exactly identicalorientation, layout, location, shape, size, amount, or other measure,but are intended to encompass nearly identical orientation, layout,location, shapes, sizes, amounts, or other measures within acceptablevariations that may occur, for example, due to manufacturing processes.The term “substantially” may be used herein to reflect this meaning.

Terms such as “about” or “approximately” may reflect sizes,orientations, or layouts that vary only in a small relative manner,and/or in a way that does not significantly alter the operation,functionality, or structure of certain elements. For example, a rangefrom “about 0.1 to about 1” may encompass a range such as a 0%-5%deviation around 0.1 and a 0% to 5% deviation around 1, especially ifsuch deviation maintains the same effect as the listed range.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present application, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

As used herein, items described as being “electrically connected” areconfigured such that an electrical signal can be passed from one item tothe other. Therefore, a passive electrically conductive component (e.g.,a wire, pad, internal electrical line, etc.) physically connected to apassive electrically insulative component (e.g., a prepreg layer of aprinted circuit board, an electrically insulative adhesive connectingtwo devices, an electrically insulative underfill or mold layer, etc.)is not electrically connected to that component. Moreover, items thatare “directly electrically connected,” to each other are electricallyconnected through one or more passive elements, such as, for example,wires, pads, internal electrical lines, resistors, etc. As such,directly electrically connected components do not include componentselectrically connected through active elements, such as transistors ordiodes.

Components described as thermally connected or in thermal communicationare arranged such that heat will follow a path between the components toallow the heat to transfer from the first component to the secondcomponent. Simply because two components are part of the same device orboard does not make them thermally connected. In general, componentswhich are heat-conductive and directly connected to otherheat-conductive or heat-generating components (or connected to thosecomponents through intermediate heat-conductive components or in suchclose proximity as to permit a substantial transfer of heat) will bedescribed as thermally connected to those components, or in thermalcommunication with those components. On the contrary, two componentswith heat-insulative materials therebetween, which materialssignificantly prevent heat transfer between the two components, or onlyallow for incidental heat transfer, are not described as thermallyconnected or in thermal communication with each other. The terms“heat-conductive” or “thermally-conductive” do not apply to any materialthat provides incidental heat conduction, but are intended to refer tomaterials that are typically known as good heat conductors or known tohave utility for transferring heat, or components having similar heatconducting properties as those materials.

Referring to FIGS. 1 and 2, an LED tube lamp of one embodiment of thepresent invention includes a lamp tube 1, an LED light strip 2 disposedinside the lamp tube 1, and two end caps 3 respectively disposed at twoends of the lamp tube 1. The lamp tube 1 may be made of plastic orglass. The sizes of the two end caps 3 may be same or different.Referring to FIG. 1A, the size of one end cap may in some embodiments beabout 30% to about 80% times the size of the other end cap.

In one embodiment, the lamp tube 1 is made of glass with strengthened ortempered structure to avoid being easily broken and incurring electricshock that may occur in conventional glass made tube lamps, and to avoidthe fast aging process that often occurs in plastic made tube lamps. Theglass made lamp tube 1 may be additionally strengthened or tempered by achemical tempering method or a physical tempering method in variousembodiments of the present invention.

Referring to FIGS. 3 and 4, in one embodiment of the invention, each endcap 3 includes an electrically insulating tube 302, a thermal conductivemember 303 sleeved over the electrically insulating tube 302, and twohollow conductive pins 301 disposed on the electrically insulating tube302. The thermal conductive member 303 can be a metal ring that istubular in shape.

During fabrication of the LED tube lamp, the rear end region 101 (alsoreferred to as an end region 101) of the lamp tube 1 is inserted intoone of the end caps 3. In some embodiments, the axial length of theinserted portion of the rear end region 101 of the lamp tube 1 accountsfor approximately one-third (⅓) to two-thirds (⅔) of the total axiallength of the thermal conductive member 303. One benefit is that, therewill be sufficient creepage distance between the hollow conductive pins301 and the thermal conductive member 303, and thus it is not easy toform a short circuit leading to dangerous electric shock to individuals.On the other hand, the creepage distance between the hollow conductivepin 301 and the thermal conductive member 303 is increased due to theelectrically insulating effect of the electrically insulating tube 302,and thus a high voltage is applied to the LED tube lamp without causingelectric shocks to people.

Referring to FIGS. 5 and 22, in one embodiment, an end cap 3′ has apillar 312 at one end, the top end of the pillar 312 is provided with anopening having a groove 314 of, for example 0.1±1% mm depth at theperiphery thereof for positioning a conductive lead 53 as shown in FIG.22. The conductive lead 53 passes through the opening on top of thepillar 312 and has its end bent to be disposed in the groove 314. Afterthat, a conductive metallic cap 311 covers the pillar 312 such that theconductive lead 53 is fixed between the pillar 312 and the conductivemetallic cap 311. In some embodiments, the inner diameter of theconductive metallic cap 311 is 7.56±5% mm, the outer diameter of thepillar 312 is 7.23±5% mm, and the outer diameter of the conductive lead53 is 0.5±1% mm. Nevertheless, the mentioned sizes are not limited hereonce that the conductive metallic cap 311 closely covers the pillar 312without using extra adhesives and therefore completes the electricalconnection between the power supply 5 and the conductive metallic cap311.

Referring to FIGS. 2 and 3, in one embodiment, the end cap 3 may haveopenings 304 to dissipate heat generated by the power supply modulesinside the end cap 3 so as to prevent a high temperature conditioninside the end cap 3 that might reduce reliability. In some embodiments,the openings are in a shape of an arc; especially in a shape of threearcs with different size. In one embodiment, the openings are in a shapeof three arcs with gradually varying size. The openings on the end cap 3can be in any one of the above-mentioned shapes or any combinationthereof.

In other embodiments, the end cap 3 is provided with a socket (notshown) for installing the power supply module.

In other embodiments, the width of the LED light strip 2 (along thecircumferential direction of the lamp tube) can be widened to occupy acircumference area of the inner circumferential surface of the lamp tube1. Since the LED light strip 2 has on its surface a circuit protectivelayer made of an ink which can reflect lights, the widened part of theLED light strip 2 functions like the reflective film. In someembodiments, a ratio of the length of the LED light strip 2 along thecircumferential direction to the circumferential length of the lamp tube1 is about 0.3 to 0.5. The light emitted from the light sources could beconcentrated by the reflection of the widened part of the LED lightstrip 2.

Furthermore, the LED light strip 2 may be an elongated aluminum plate,FR 4 board, or a bendable circuit sheet. When the lamp tube 1 is made ofglass, adopting a rigid aluminum plate or FR4 board would make a brokenlamp tube, e.g., broken into two parts, remain a straight shape so thata user may be under a false impression that the LED tube lamp is stillusable and fully functional, and it is easy for him to incur electricshock upon handling or installation of the LED tube lamp. Because ofadded flexibility and bendability of the flexible substrate for the LEDlight strip 2, the problem faced by the aluminum plate, FR4 board, orconventional 3-layered flexible board having inadequate flexibility andbendability, are thereby addressed. In certain embodiments, a bendablecircuit sheet is adopted as the LED light strip 2 such that an LED lightstrip 2 would not allow a ruptured or broken lamp tube to maintain astraight shape and therefore would instantly inform the user of thedisability of the LED tube lamp and avoid possibly incurred electricshock. The following are further descriptions of an example bendablecircuit sheet used as the LED light strip 2.

Referring to FIG. 7, in one example of the LED light strip 2, a bendablecircuit sheet includes a wiring layer 2 a with conductive effect. TheLED light source 202 is configured on the wiring layer 2 a andelectrically connect to the power through the wiring layer 2 a. Thewiring layer with conductive effect, in this specification, is alsocalled a conductive layer. Referring to FIG. 7 again, in one embodiment,the LED light strip 2 includes a bendable circuit sheet having aconductive wiring layer 2 a and a dielectric layer 2 b that are arrangedin a stacked manner, wherein the wiring layer 2 a and the dielectriclayer 2 b have the same areas. The LED light source 202 is disposed onone surface of the wiring layer 2 a, the dielectric layer 2 b isdisposed on the other surface of the wiring layer 2 a that is away fromthe LED light sources 202. The wiring layer 2 a is electricallyconnected to the power supply 5 to carry direct current (DC) signals.Meanwhile, the surface of the dielectric layer 2 b away from the wiringlayer 2 a is fixed to the inner circumferential surface of the lamp tube1 by means of the adhesive sheet 4. The wiring layer 2 a can be a metallayer or a power supply layer including wires such as copper wires.

In another embodiment, the outer surface of the wiring layer 2 a or thedielectric layer 2 b may be covered with a circuit protective layer madeof an ink with function of resisting soldering and increasingreflectivity. Alternatively, the dielectric layer can be omitted and thewiring layer can be directly bonded to the inner circumferential surfaceof the lamp tube, and the outer surface of the wiring layer 2 a iscoated with the circuit protective layer. Whether the wiring layer 2 ahas a one-layered, or two-layered structure, the circuit protectivelayer can be adopted. In some embodiments, the circuit protective layeris disposed only on one side/surface of the LED light strip 2, such asthe surface having the LED light source 202. In some embodiments, thebendable circuit sheet is a one-layered structure made of just onewiring layer 2 a, or a two-layered structure made of one wiring layer 2a and one dielectric layer 2 b, and thus is more bendable or flexible tocurl when compared with the conventional three-layered flexiblesubstrate (one dielectric layer sandwiched with two wiring layers). As aresult, the bendable circuit sheet of the LED light strip 2 can beinstalled in a lamp tube with a customized shape or non-tubular shape,and fitly mounted to the inner surface of the lamp tube. The bendablecircuit sheet closely mounted to the inner surface of the lamp tube ispreferable in some cases. In addition, using fewer layers of thebendable circuit sheet improves the heat dissipation, lowering thematerial cost, being more environmental friendly, and has the ability toincrease the flexible effect.

Nevertheless, the bendable circuit sheet is not limited to beingone-layered or two-layered; in other embodiments, the bendable circuitsheet may include multiple layers of the wiring layers 2 a and multiplelayers of the dielectric layers 2 b, in which the dielectric layers 2 band the wiring layers 2 a are sequentially stacked in a staggeredmanner, respectively. These stacked layers are away from the surface ofthe outermost wiring layer 2 a which has the LED light source 202disposed thereon and is electrically connected to the power supply 5.Moreover, in some embodiments, the length of the bendable circuit sheetis greater than the length of the lamp tube.

Referring to FIG. 23, in one embodiment, the LED light strip 2 includesa bendable circuit sheet having in sequence a first wiring layer 2 a, adielectric layer 2 b, and a second wiring layer 2 c. The thickness ofthe second wiring layer 2 c is greater than that of the first wiringlayer 2 a, and the length of the LED light strip 2 is greater than thatof the lamp tube 1. The end region of the LED light strip 2 extendingbeyond the end portion of the lamp tube 1 without disposition of thelight source 202 is formed with two separate through holes 203 and 204to respectively electrically communicate between the first wiring layer2 a and the second wiring layer 2 c. The through holes 203 and 204 arenot in communication with each other to avoid short.

In this way, the greater thickness of the second wiring layer 2 c allowsthe second wiring layer 2 c to support the first wiring layer 2 a andthe dielectric layer 2 b, and meanwhile allow the LED light strip 2 tobe mounted onto the inner circumferential surface without being liableto shift or deform, and thus the yield rate of products can be improved.In addition, the first wiring layer 2 a and the second wiring layer 2 care in electrical communication such that the circuit layout of thefirst wiring later 2 a can be extended downward to the second wiringlayer 2 c to reach the circuit layout of the entire LED light strip 2.Moreover, since the land for the circuit layout becomes two-layered, thearea of each single layer and therefore the width of the LED light strip2 can be reduced such that more LED light strips 2 can be put on aproduction line to increase productivity.

Furthermore, the first wiring layer 2 a and the second wiring layer 2 cof the end region of the LED light strip 2 that extends beyond the endportion of the lamp tube 1 without disposition of the light source 202can be used to accomplish the circuit layout of a power supply module sothat the power supply module can be directly disposed on the bendablecircuit sheet of the LED light strip 2.

Referring to FIG. 2, in one embodiment, the LED light strip 2 has aplurality of LED light sources 202 mounted thereon, and the end cap 3has a power supply 5 installed therein. The LED light sources 202 andthe power supply 5 are electrically connected by the LED light strip 2.The power supply 5 may be a single integrated unit (i.e., all of thepower supply components are integrated into one module unit) installedin one end cap 3. Alternatively, the power supply 5 may be divided intotwo separate units (i.e. the power supply components are divided intotwo parts) installed in two end caps 3, respectively. When only one endof the lamp tube 1 is strengthened by a glass tempering process, it maybe preferable that the power supply 5 is a single integrated unit andinstalled in the end cap 3 corresponding to the strengthened end 101 ofthe lamp tube 1.

The power supply 5 can be fabricated by various ways. For example, thepower supply 5 may be an encapsulation body formed by injection moldinga silica gel with high thermal conductivity such as being greater than0.7 w/m·k. This kind of power supply has advantages of high electricalinsulation, high heat dissipation, and regular shape to match othercomponents in an assembly. Alternatively, the power supply 5 in the endcaps 3 may be a printed circuit board having components (e.g., powerconverting and/or generating components) that are directly exposed orpackaged by a conventional heat shrink sleeve. The power supply 5according to some embodiments of the present invention can be a singleprinted circuit board provided with a power supply module as shown inFIG. 6 or a single integrated unit as shown in FIG. 21.

Referring to FIGS. 2 and 21, in one embodiment of the present invention,the power supply 5 is provided with a male plug 51 at one end and ametal pin 52 at the other end, one end of the LED light strip 2 iscorrespondingly provided with a female plug 201, and the end cap 3 isprovided with a hollow conductive pin 301 to be connected with an outerelectrical power source. Specifically, the male plug 51 is fittinglyinserted into the female plug 201 of the LED light strip 2, while themetal pins 52 are fittingly inserted into the hollow conductive pins 301of the end cap 3. The male plug 51 and the female plug 201 function as aconnector between the power supply 5 and the LED light strip 2. Uponinsertion of the metal pin 52, the hollow conductive pin 301 is punchedwith an external punching tool to slightly deform such that the metalpin 52 of the power supply 5 is secured and electrically connected tothe hollow conductive pin 301. Upon turning on the electrical power, theelectrical current passes in sequence through the hollow conductive pin301, the metal pin 52, the male plug 51, and the female plug 201 toreach the LED light strip 2 and go to the LED light sources 202.However, the power supply 5 of the present invention is not limited tothe modular type as shown in FIG. 21. The power supply 5 may be aprinted circuit board provided with a power supply module andelectrically connected to the LED light strip 2 via the abovementionedthe male plug 51 and female plug 201 combination.

In another embodiment, a traditional wire bonding technique can be usedinstead of the male plug 51 and the female plug 201 for connecting anykind of the power supply 5 and the light strip 2. That is, a traditionalmetal wire can be applied to, and one end of the metal wire electricallyconnects to the power supply and the other end electrically connects tothe LED light strip 2. Furthermore, the wires may be wrapped with anelectrically insulating tube to protect a user from being electricallyshocked. However, the bonded wires tend to be easily broken duringtransportation and can therefore cause quality issues.

In still another embodiment, the connection between the power supply 5and the LED light strip 2 may be accomplished via soldering (e.g., tinsoldering), rivet bonding, or welding. One way to secure the LED lightstrip 2 is to provide the adhesive sheet 4 at one side thereof andadhere the LED light strip 2 to the inner surface of the lamp tube 1 viathe adhesive sheet 4. Two ends of the LED light strip 2 can be eitherfixed to or detached from the inner surface of the lamp tube 1.

In case that two ends of the LED light strip 2 are fixed to the innersurface of the lamp tube 1, it may be preferable that the bendablecircuit sheet of the LED light strip 2 is provided with the female plug201 and the power supply is provided with the male plug 51 to accomplishthe connection between the LED light strip 2 and the power supply 5. Inthis case, the male plug 51 of the power supply 5 is inserted into thefemale plug 201 to establish electrical connection.

In case that two ends of the LED light strip 2 are detached from theinner surface of the lamp tube 1 and that the LED light strip 2 isconnected to the power supply 5 via wire-bonding, any movement insubsequent transportation may cause the bonded wires to break.Therefore, a desirable option for the connection between the LED lightstrip 2 and the power supply 5 could be soldering. Specifically,referring to FIG. 6, the ends of the LED light strip 2 including thebendable circuit sheet are arranged to pass over the strengthenedtransition region 103 and directly soldering bonded to an outputterminal of the power supply 5 such that the product quality is improvedwithout using wires (e.g., wire-bonding wires). In this way, the femaleplug 201 and the male plug 51 respectively provided for the LED lightstrip 2 and the power supply 5 are no longer needed.

Referring to FIG. 8, an output terminal of the printed circuit board ofthe power supply 5 may have soldering pads “a” provided with an amountof solder (e.g., tin solder) with a thickness sufficient to later form asolder joint. Correspondingly, the ends of the LED light strip 2 mayhave soldering pads “b”. The soldering pads “a” on the output terminalof the printed circuit board of the power supply 5 are soldered to thesoldering pads “b” on the LED light strip 2 via the tin solder on thesoldering pads “a”. The soldering pads “a” and the soldering pads “b”may be face to face during soldering such that the connection betweenthe LED light strip 2 and the printed circuit board of the power supply5 is the most firm. However, this kind of soldering typically includesthat a thermo-compression head presses on the rear surface of the LEDlight strip 2 and heats the tin solder, i.e. the LED light strip 2intervenes between the thermo-compression head and the tin solder, andtherefore may easily cause reliability problems. Referring to FIG. 14, athrough hole may be formed in each of the soldering pads “b” on the LEDlight strip 2 to allow the soldering pads “b” overlay the soldering pads“b” without being face-to-face and the thermo-compression head directlypresses tin solders on the soldering pads “a” on surface of the printedcircuit board of the power supply 5 when the soldering pads “a” and thesoldering pads “b” are vertically aligned.

Referring again to FIGS. 6 and 8, two ends of the LED light strip 2detached from the inner surface of the lamp tube 1 are formed as freelyextending end portions 21, while most of the LED light strip 2 isattached and secured to the inner surface of the lamp tube 1. Most ofthe LED light strip 2 is therefore at a first vertical level, while thefreely extending end portion 21 extends to a second vertical level, andmay be at a plurality of different vertical levels as it extends along alength of the lamp tube 1. The first vertical level may be closer to thelamp tube 1, while the second vertical level may be closer to theprinted circuit board of the power supply 5. For example, as can be seenin FIGS. 6 and 8, the freely extending end portions 21 may extendbetween a first vertical level at which the LED light strip 2 isdisposed where the light strip 2 includes light sources 202, and asecond vertical level at which a printed circuit board of the powersupply 5 is disposed. One of the freely extending end portions 21 hasthe soldering pads “b” as mentioned above. Upon assembling of the LEDtube lamp, the freely extending end portions 21 along with the solderedconnection of the printed circuit board of the power supply 5 and theLED light strip 2 would be coiled, curled up or deformed to be fittinglyaccommodated inside the lamp tube 1. When the bendable circuit sheet ofthe LED light strip 2 includes in sequence the first wiring layer 2 a,the dielectric layer 2 b, and the second wiring layer 2 c as shown inFIG. 23, the freely extending end portions 21, which are the end regionsof the LED light strip 2 extending beyond the lamp tube 1 withoutdisposition of the light sources 202, can be used to accomplish theconnection between the first wiring layer 2 a and the second wiringlayer 2 c and arrange the circuit layout of the power supply 5.

In one embodiment, during the connection of the LED light strip 2 andthe power supply 5, the soldering pads “b” and the soldering pads “a”and the LED light sources 202 are on surfaces facing toward the samedirection (e.g., they may both be facing up in one example) and thesoldering pads “b” on the LED light strip 2 are each formed with athrough hole “e” as shown in FIG. 14 such that the soldering pads “b”and the soldering pads “a” communicate with each other via the throughholes “e”. When the freely extending end portions 21 are deformed due tocontraction or curling up, the soldered connection of the printedcircuit board of the power supply 5 and the LED light strip 2 exerts alateral tension on the power supply 5. Furthermore, the solderedconnection of the printed circuit board of the power supply 5 and theLED light strip 2 also exerts a downward tension on the power supply 5when compared with the situation where the soldering pads “a” of thepower supply 5 and the soldering pads “b” of the LED light strip 2 areface to face. This downward tension on the power supply 5 comes from thetin solders inside the through holes “e” and forms a stronger and moresecure electrical connection between the LED light strip 2 and the powersupply 5.

Referring to FIG. 9, in one embodiment, the soldering pads “b” of theLED light strip 2 are two separate pads to electrically connect thepositive and negative electrodes of the bendable circuit sheet of theLED light strip 2, respectively. The size of the soldering pads “b” maybe, for example, about 3.5×2 mm². The printed circuit board of the powersupply 5 is correspondingly provided with soldering pads “a” havingreserved tin solders, and the height of the tin solders suitable forsubsequent automatic soldering bonding process is generally, forexample, about 0.1 to 0.7 mm, in some embodiments about 0.3 to about 0.5mm, and in some additional embodiments about 0.4 mm. An electricallyinsulating through hole “c” may be formed between the two soldering pads“b” to isolate and prevent the two soldering pads from electricallyshorting during soldering. Furthermore, an extra positioning opening “d”may also be provided behind the electrically insulating through hole “c”to allow an automatic soldering machine to quickly recognize theposition of the soldering pads “b”.

For the sake of achieving scalability and compatibility, the amount ofthe soldering pads “b” on each end of the LED light strip 2 may be morethan one such as two, three, four, or more than four. When there is onlyone soldering pad “b” provided at each end of the LED light strip 2, thetwo ends of the LED light strip 2 are electrically connected to thepower supply 5 to form a loop, and various electrical components can beused. For example, a capacitance may be replaced by an inductance toperform current regulation. In this specification, the meaning of“inductance” includes “inductor”, the meaning of “capacitance” includes“capacitor”, and the meaning of “resistance” includes “resistor”.Referring to FIGS. 10 to 13, when each end of the LED light strip 2 hasthree soldering pads, the third soldering pad can be grounded; when eachend of the LED light strip 2 has four soldering pads, the fourthsoldering pad can be used as a signal input terminal. Correspondingly,in some embodiments, the power supply 5 should have same amount ofsoldering pads “a” as that of the soldering pads “b” on the LED lightstrip 2. In some embodiments, as long as electrical short between thesoldering pads “b” can be prevented, the soldering pads “b” should bearranged according to the dimension of the actual area for disposition,for example, three soldering pads can be arranged in a row or two rows.In other embodiments, the amount of the soldering pads “b” on thebendable circuit sheet of the LED light strip 2 may be reduced byrearranging the circuits on the bendable circuit sheet of the LED lightstrip 2. The lesser the amount of the soldering pads, the easier thefabrication process becomes. On the other hand, a greater number ofsoldering pads may improve and secure the electrical connection betweenthe LED light strip 2 and the output terminal of the power supply 5.

Referring to FIG. 14, in another embodiment, each soldering pads “b” isformed with a through hole “e” having a diameter generally of about 1 to2 mm, in some embodiments of about 1.2 to 1.8 mm, and in yet furtherembodiments of about 1.5 mm. The through hole “e” communicates thesoldering pad “a” with the soldering pad “b” so that the tin solder onthe soldering pads “a” passes through the through holes “e” and finallyreaches the soldering pads “b”. A smaller through hole “e” would make itdifficult for the tin solder to pass. The tin solder accumulates aroundthe through holes “e” upon exiting the through holes “e” and condensesto form a solder ball “g” with a larger diameter than that of thethrough holes “e” upon condensing. Such a solder ball “g” functions as arivet to further increase the stability of the electrical connectionbetween the soldering pads “a” on the power supply 5 and the solderingpads “b” on the LED light strip 2.

Referring to FIGS. 15 to 16, in other embodiments, when a distance fromthe through hole “e” to the side edge of the LED light strip 2 is lessthan 1 mm, the tin solder may pass through the through hole “e” toaccumulate on the periphery of the through hole “e”, and extra tinsolder may spill over the soldering pads “b” to reflow along the sideedge of the LED light strip 2 and join the tin solder on the solderingpads “a” of the power supply 5. The tin solder then condenses to form astructure like a rivet to firmly secure the LED light strip 2 onto theprinted circuit board of the power supply 5 such that reliableelectrical connection is achieved. Referring to FIGS. 17 and 18, inanother embodiment, the through hole “e” can be replaced by a notch “f”formed at the side edge of the soldering pads “b” to allow the tinsolder to easily pass through the notch “f” and accumulate on theperiphery of the notch “f” and to form a solder ball with a largerdiameter than that of the notch “e” upon condensing. Such a solder ballmay be formed like a C-shape rivet to enhance the secure capability ofthe electrically connecting structure.

The abovementioned through hole “e” or notch “f” might be formed inadvance of soldering or formed by direct punching with athermo-compression head during soldering. The portion of thethermo-compression head for touching the tin solder may be flat,concave, or convex, or any combination thereof. The portion of thethermo-compression head for restraining the object to be soldered suchas the LED light strip 2 may be strip-like or grid-like. The portion ofthe thermo-compression head for touching the tin solder does notcompletely cover the through hole “e” or the notch “f” to make sure thatthe tin solder is able to pass through the through hole “e” or the notch“f”. The portion of the thermo-compression head being concave mayfunction as a room to receive the solder ball. In other embodiments, thebendable circuit sheet of the LED light strip 2 has a position hole toprovide a precisely position recognition for the soldering pads “a” ofthe power supply 5 to weld the soldering pads “b” on the LED light strip2 during welding.

Referring to FIGS. 19 and 20, in another embodiment, the LED light strip2 and the power supply 5 may be connected by utilizing a circuit boardassembly 25 configured a power supply module 250 instead of solderingbonding. The circuit board assembly 25 has a long circuit sheet 251 anda short circuit board 253 that are adhered to each other with the shortcircuit board 253 being adjacent to the side edge of the long circuitsheet 251. The short circuit board 253 may be provided with the powersupply module 250 to form the power supply 5. The short circuit board253 is stiffer or more rigid than the long circuit sheet 251 to be ableto support the power supply module 250.

The long circuit sheet 251 may be the bendable circuit sheet of the LEDlight strip 2 including a wiring layer 2 a as shown in FIG. 7. Thewiring layer 2 a of the LED light strip 2 and the power supply module250 may be electrically connected in various manners depending on thedemand in practice. As shown in FIG. 19, the power supply module 250 andthe long circuit sheet 251 having the wiring layer 2 a on surface are onthe same side of the short circuit board 253 such that the power supplymodule 250 is directly connected to the long circuit sheet 251. As shownin FIG. 20, alternatively, the power supply module 250 and the longcircuit sheet 251 including the wiring layer 2 a on surface are onopposite sides of the short circuit board 253 such that the power supplymodule 250 is directly connected to the short circuit board 253 andindirectly connected to the wiring layer 2 a of the LED light strip 2 byway of the short circuit board 253.

FIG. 24A is a block diagram of a system including an LED tube lampincluding a power supply module according to certain embodiments.Referring to FIG. 24A, an AC power supply 508 is used to supply an ACsupply signal. A lamp driving circuit 505 receives the AC supply signalfrom the AC power supply 508 and then converts it into an AC drivingsignal. An LED tube lamp 500 receives the AC driving signal from thelamp driving circuit 505 and is thus driven to emit light. In thisembodiment, the LED tube lamp 500 is power-supplied at its both end capsrespectively having two pins 501 and 502 and two pins 503 and 504, whichare coupled to the lamp driving circuit 505 to concurrently receive theAC driving signal to drive an LED unit (not shown) in the LED tube lamp500 to emit light. However, in other embodiments, each end cap of theLED tube lamp could have only at least one pin for receiving the ACdriving signal. That is, it is unnecessary to have two pins used in eachend cap for the purpose of passing electricity through the both ends ofthe LED tube lamp 500. In the present embodiment, the AC power supply508 could be commercial electricity with 100-277 voltages in frequencyof 50 Hz or 60 Hz. The lamp driving circuit 505 receives the AC supplysignal from the AC power supply 508 and then converts it into the ACdriving signal as an external driving signal. The lamp driving circuit505 could be an electronic ballast and is used to convert the signal ofcommercial electricity into high-frequency and high-voltage AC drivingsignal. The common types of electronic ballast, such as instant-startelectronic ballast, program-start electronic ballast, and rapid-startelectronic ballast, can be applied to the LED tube lamp of the presentinvention. In some embodiments, the voltage of the AC driving signal isbigger than 300V and prefers 400-700V with frequency being higher than10 kHz and preferring 20-50 kHz. FIG. 24B is a block diagram of an LEDlamp according to certain embodiments. Referring to FIG. 24B, the powersupply module of the LED lamp summarily includes a rectifying circuit510, a filtering circuit 520, and a rectifying circuit 540, and maycomprise a portion of an LED lighting module 530. The power supplymodule of the LED lamp could be used in the LED tube lamp 500 with adual-end power supply in FIG. 24A. The rectifying circuit 510 is coupledto pins 501 and 502 to receive and then rectify an external drivingsignal conducted by pins 501 and 502. The rectifying circuit 540 iscoupled to pins 503 and 504 to receive and then rectify an externaldriving signal conducted by pins 503 and 504. Therefore, the powersupply module of the LED lamp may include two rectifying circuits 510and 540 configured to output a rectified signal at output terminals 511and 512. The filtering circuit 520 is coupled to the output terminals511 and 512 to receive and then filter the rectified signal, so as tooutput a filtered signal to filtering output terminals 521 and 522. TheLED lighting module 530 is coupled to the filtering output terminals 521and 522 to receive the filtered signal and thereby to drive an LED unit(not shown) in the LED lighting module 530 to emit light.

FIG. 25A is a schematic diagram of a rectifying circuit according to anembodiment of the present invention. Referring to FIG. 25A, a rectifyingcircuit 610, i.e. a bridge rectifier, includes four rectifying diodes611, 612, 613, and 614, configured to full-wave rectify a receivedsignal. The diode 611 has an anode connected to the output terminal 512,and a cathode connected to the pin 502. The diode 612 has an anodeconnected to the output terminal 512, and a cathode connected to the pin501. The diode 613 has an anode connected to the pin 502, and a cathodeconnected to the output terminal 511. The diode 614 has an anodeconnected to the pin 501, and a cathode connected to the output terminal511.

When the pins 501 and 502 receive an AC signal, the rectifying circuit610 operates as follows. During the connected AC signal's positive halfcycle, the AC signal is input through the pin 501, the diode 614, andthe output terminal 511 in sequence, and later output through the outputterminal 512, the diode 611, and the pin 502 in sequence. During theconnected AC signal's negative half cycle, the AC signal is inputthrough the pin 502, the diode 613, and the output terminal 511 insequence, and later output through the output terminal 512, the diode612, and the pin 501 in sequence. Therefore, during the connected ACsignal's full cycle, the positive pole of the rectified signal producedby the rectifying circuit 610 keeps at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the rectified signal produced or output by therectifying circuit 610 is a full-wave rectified signal.

When the pins 501 and 502 are coupled to a DC power supply to receive aDC signal, the rectifying circuit 610 operates as follows. When the pin501 is coupled to the positive end of the DC power supply and the pin502 to the negative end of the DC power supply, the DC signal is inputthrough the pin 501, the diode 614, and the output terminal 511 insequence, and later output through the output terminal 512, the diode611, and the pin 502 in sequence. When the pin 501 is coupled to thenegative end of the DC power supply and the pin 502 to the positive endof the DC power supply, the DC signal is input through the pin 502, thediode 613, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 612, and the pin 501 insequence. Therefore, no matter what the electrical polarity of the DCsignal is between the pins 501 and 502, the positive pole of therectified signal produced by the rectifying circuit 610 keeps at theoutput terminal 511, and the negative pole of the rectified signalremains at the output terminal 512.

Therefore, the rectifying circuit 610 in this embodiment can output orproduce a proper rectified signal regardless of whether the receivedinput signal is an AC or DC signal.

FIG. 25B is a schematic diagram of a rectifying circuit according to anembodiment of the present invention. Referring to FIG. 25B, a rectifyingcircuit 710 includes two rectifying diodes 711 and 712 configured tohalf-wave rectify a received signal. The diode 711 has an anodeconnected to the pin 502, and a cathode connected to the output terminal511. The diode 712 has an anode connected to the output terminal 511,and a cathode connected to the pin 501. The output terminal 512 may beomitted or grounded depending on applications in practice.

Next, exemplary operation(s) of the rectifying circuit 710 is describedas follows.

In one embodiment, during a received AC signal's positive half cycle,the electrical potential at the pin 501 is higher than that at the pin502, so the diodes 711 and 712 are both in a cutoff state as beingreverse-biased and make the rectifying circuit 710 stop outputting arectified signal. During a received AC signal's negative half cycle, theelectrical potential at the pin 501 is lower than that at the pin 502,so the diodes 711 and 712 are both in a conducting state as beingforward-biased and allow the AC signal to be input through the diode 711and the output terminal 511, and later to be output through the outputterminal 512, a ground terminal, or another end of the LED lamp which isnot directly connected to the rectifying circuit 710. Accordingly, therectified signal produced or output by the rectifying circuit 710 is ahalf-wave rectified signal.

FIG. 25C is a schematic diagram of a rectifying circuit according to anembodiment of the present invention. Referring to FIG. 25C, a rectifyingcircuit 810 includes a rectifying unit 815 and a terminal adaptercircuit 541. In this embodiment, the rectifying unit 815 comprises ahalf-wave rectifier circuit including two diodes 811 and 812, and isconfigured to half-wave rectification. The diode 811 has an anodeconnected to an output terminal 512, and a cathode connected to ahalf-wave node 819. The diode 812 has an anode connected to thehalf-wave node 819, and a cathode connected to an output terminal 511.The terminal adapter circuit 541 is coupled to the half-wave node 819and the pins 501 and 502 to transmit a signal received at the pin 501and/or the pin 502 to the half-wave node 819. By means of the terminaladapting function of the terminal adapter circuit 541, the rectifyingcircuit 810 allows of two input terminals (connected to the pins 501 and502) and two output terminals 511 and 512.

Next, in certain embodiments, the rectifying circuit 810 operates asfollows.

During a received AC signal's positive half cycle, the AC signal may beinput through the pin 501 or 502, the terminal adapter circuit 541, thehalf-wave node 819, the diode 812, and the output terminal 511 insequence, and later output through another end or circuit of the LEDtube lamp. During a received AC signal's negative half cycle, the ACsignal may be input through another end or circuit of the LED tube lamp,and later output through the output terminal 512, the diode 811, thehalf-wave node 819, the terminal adapter circuit 541, and the pin 501 or502 in sequence.

It's worth noting that the terminal adapter circuit 541 may includeresistor(s), capacitor(s), inductor(s), or any combination thereof, forperforming at least one of functions of current/voltage limiting, typesof protection, current/voltage regulation, and so forth. Descriptions ofthese functions are presented below.

In practice, the rectifying unit 815 and terminal adapter circuit 541may be interchanged in position (as shown in FIG. 25D) without alteringthe function of half-wave rectification. FIG. 25D is a schematic diagramof a rectifying circuit according to an embodiment of the presentinvention. Referring to FIG. 25D, the diode 811 has an anode connectedto the pin 502 and the diode 812 has a cathode connected to the pin 501.The cathode of diode 811 and the anode of diode 812 are connected to thehalf-wave node 819. The terminal adapter circuit 541 is coupled to thehalf-wave node 819 and the output terminals 511 and 512. During areceived AC signal's positive half cycle, the AC signal may be inputthrough another end or circuit of the LED tube lamp, and later outputthrough the output terminal 512 or 511, the terminal adapter circuit541, the half-wave node 819, the diode 812, and the pin 501 in sequence.During a received AC signal's negative half cycle, the AC signal may beinput through the pin 502, the diode 811, the half-wave node 819, theterminal adapter circuit 541, and the output terminal 511 or 512 insequence, and later output through another end or circuit of the LEDtube lamp.

It is noticeable that the terminal adapter circuit 541 in embodimentsshown in FIGS. 25C and 25D may be omitted and is therefore depicted by adotted line. If the terminal adapter circuit 541 of FIG. 25C is omitted,the pins 501 and 502 will be coupled to the half-wave node 819. If theterminal adapter circuit 541 of FIG. 25D is omitted, the outputterminals 511 and 512 will be coupled to the half-wave node 819.

The rectifying circuit as shown and explained in FIGS. 25A-D canconstitute or be the rectifying circuit 540 shown in FIG. 24B, as havingthe pins 503 and 504 for conducting instead of the pins 501 and 502.

Next, an explanation follows as to choosing embodiments and theircombinations of the rectifying circuits 510 and 540, with reference toFIG. 24B.

The rectifying circuits 510 and 540 in embodiments shown in FIG. 24B mayeach comprise any one of the rectifying circuits in FIGS. 25A-D, and theterminal adapter circuit 541 in FIGS. 25C-D may be omitted withoutaltering the rectification function used by an LED tube lamp. When therectifying circuits 510 and 540 each comprise a half-wave rectifiercircuit described in FIGS. 25B-D, during a received AC signal's positiveor negative half cycle, the AC signal may be input to either therectifying circuit 510 or the rectifying circuit 540, and later outputfrom another. Further, when the rectifying circuits 510 and 540 eachcomprise the rectifying circuit described in FIG. 25C or 25D, or whenthey comprise the rectifying circuits in FIGS. 25C and 25D individually,only one terminal adapter circuit 541 may be needed for functions ofcurrent/voltage limiting, types of protection, current/voltageregulation, etc. within the rectifying circuits 510 and 540, and anotherterminal adapter circuit 541 within the rectifying circuit 510 or 540can be ignored.

FIG. 26A is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.26A, a terminal adapter circuit 641 includes a capacitor 642 having anend connected to the pins 501 and 502, and the other end thereofconnected to the half-wave node 819. The capacitor 642 has an equivalentimpedance to an AC signal. This impedance increases as the frequency ofthe AC signal decreases, and decreases as the frequency increases.Therefore, the capacitor 642 in the terminal adapter circuit 641 in thisembodiment works as a high-pass filter. Further, the terminal adaptercircuit 641 is connected in series to an LED unit in the LED tube lamp,producing an equivalent impedance of the terminal adapter circuit 641 toperform a current/voltage limiting function on the LED unit, therebypreventing damaging of the LED unit from an excessive voltage acrossand/or current in the LED unit. In addition, selecting the capacitancevalue of the capacitor 642 according to the frequency of the AC signalcan further enhance current/voltage regulation to the LED assembly.

It's worth noting that the terminal adapter circuit 641 may furtherinclude a capacitor 645 and/or capacitor 646. The capacitor 645 has anend connected to the half-wave node 819, and the other end connected tothe pin 503. The capacitor 646 has an end connected to the half-wavenode 819, and the other end connected to the pin 504. For example, thehalf-wave node 819 may be a common connection node between thecapacitors 645 and 646. And the capacitor 642 acting as a currentregulating capacitor is coupled to the common connection node and thepins 501 and 502. In such a structure, the series-connected capacitors642 and 645 exist between one of the pins 501 and 502 and the pin 503,and/or the series-connected capacitors 642 and 646 exist between one ofthe pins 501 and 502 and the pin 504. Through equivalent impedances ofseries-connected capacitors, voltages from the AC signal are divided.The divided voltage on the capacitors 645 and 646 prefers 100-500V, and300-400V would be a preferred range.

Referring to FIGS. 24B and 26A, according to the ratios betweenequivalent impedances of the series-connected capacitors, the voltagesrespectively across the capacitor 642 in the rectifying circuit 510, thefiltering circuit 520, and the LED lighting module 530 can be controlledto make the current flowing through an LED module in the LED lightingmodule 530 being limited within a current rating, and then toprotect/prevent the filtering circuit 520 and the LED lighting module530 from being damaged by excessive voltages.

FIG. 26B is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.26B, a terminal adapter circuit 741 includes two capacitors 743 and 744.The capacitor 743 has an end connected to the pin 501, and the other endconnected to the half-wave node 819. The capacitor 744 has an endconnected to the pin 502, and the other end connected to the half-wavenode 819. Compared to the terminal adapter circuit 641 in FIG. 26A, theterminal adapter circuit 741 has the capacitors 743 and 744 in place ofthe capacitor 642. The capacitance values of the capacitors 743 and 744may be the same as each other, or may differ from each other dependingon the magnitudes of signals received by the pins 501 and 502.

Also, the terminal adapter circuit 741 may further comprise a capacitor745 and/or a capacitor 746, and two of them are respectively connectedto the pins 503 and 504. Thus, each of the pins 501 and 502 and each ofthe pins 503 and 504 may be connected to a capacitor in series toachieve the functions of voltage division and other protections.

FIG. 26C is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.26C, a terminal adapter circuit 841 includes three capacitors 842, 843,and 844. The capacitors 842 and 843 are connected in series between thepin 501 and the half-wave node 819. The capacitors 842 and 844 areconnected in series between the pin 502 and the half-wave node 819. Insuch a circuit structure, if any one of the capacitors 842, 843, and 844is shorted, there is still at least one capacitor (of the other twocapacitors) between the pin 501 and the half-wave node 819 and betweenthe pin 502 and the half-wave node 819, which performs acurrent-limiting function. Therefore, in the event that a useraccidentally gets an electric shock, this circuit structure will preventan excessive current from flowing through and then seriously hurting thebody of the user.

Likewise, the terminal adapter circuit 841 may further include acapacitor 845 and/or a capacitor 846, and two of them are respectivelyconnected to the pins 503 and 504. Thus, each of the pins 501 and 502and each of the pins 503 and 504 may be connected to a capacitor inseries to achieve the functions of voltage division and otherprotections.

FIG. 26D is a schematic diagram of the terminal adapter circuitaccording to an embodiment of the present invention. Referring to FIG.26D, a terminal adapter circuit 941 includes two fuses 947 and 948. Thefuse 947 has an end connected to the pin 501, and the other endconnected to the half-wave node 819. The fuse 948 has an end connectedto the pin 502, and the other end connected to the half-wave node 819.With the fuses 947 and 948, when the current passing through each of thepins 501 and 502 exceeds the current threshold corresponding to the fuse947 or 948, the corresponding fuse 947 or 948 will accordingly melt andthen break the circuit to achieve overcurrent protection.

Each of the embodiments for the terminal adapter circuits coupled to thepins 501 and 502 mentioned above can be used or included in therectifying circuit 540 when the pins 503 and 504 and the pins 501 and502 are interchanged in position.

Capacitance values of the capacitors in the embodiments of the terminaladapter circuits shown and described above, in some embodiments forexample, are desirable to be in the range of about 100 pF-100 nF. Also,a capacitor used in the embodiments may be equivalently replaced by twoor more capacitors connected in series or parallel. For example, each ofthe capacitors 642 and 842 may be replaced by two series-connectedcapacitors, one having a capacitance value chosen from the range of, forexample, about 1.0 nF to 2.5 nF and being 1.5 nF in some embodiments,and another having a capacitance value chosen from the range of, such asabout 1.5 nF to 3.0 nF and being 2.2 nF in some embodiments.

FIG. 43 is a circuit diagram of an LED lamp according to someembodiments of the present disclosure. In these embodiment(s)illustrated in FIG. 43, a compatible circuit 140 (for the LED lamp to becompatible with e.g. an external AC power supply 508, as described inthis disclosure) is present which is electrically connected between thethird pin B1 (or 503 herein) and the fourth pin B2 (or 504 herein),other than the first pin A1 (or 501 herein) and the second pin A2 (or502 herein). The compatible circuit 140 includes or allows a firstunidirectional current path I1 and a second unidirectional current path12. The first unidirectional current path I1 electrically connects tothe LED (lighting) module 130, to allow a current to flow from the LED(lighting) module 130 to one of the pins B1 and B2. The LED (lighting)module 130 includes at least one LED 135, an inductor L1, a diode D, anda transistor switch Q1, and is comparable to the LED lighting module 530herein, wherein inductor L1, diode D, and transistor switch Q1 arecomparable to driving circuit 1930 herein. The second unidirectionalcurrent path 12 electrically connects to the filtering unit 120, toallow a current to flow from one of the pins B1 and B2 to the filteringunit 120. The filtering unit 120 includes two capacitors C1 and C2 andan inductor L2, and is comparable to the filtering unit 723 herein.Also, as shown in FIG. 43, a rectifying unit 110 comprising diodes D1,D2, D3, and D4 is coupled between the first and second pins A1 and A2and the filtering unit 120, and is comparable to the rectifying circuit510 herein.

In these embodiments, the compatible circuit 140 includes diodes D5 andD6, a capacitor C3, and fuses F1 and F2. A cathode of the diode D5 iselectrically connected to the filtering unit 120; an anode of the diodeD5 is electrically connected to both an end of capacitor C3 and acathode of the diode D6; and an anode of the diode D6 is electricallyconnected to the filtering unit 120. The other end of capacitor C3 iselectrically connected to the fuses F1 and F2, which are electricallyconnected to pins B1 and B2 respectively. The capacitor C3 can preventor reduce the risk of a user accidentally touching electricallyconducting part(s) of the LED lamp and thus getting electrically shockedwhen the user is installing the LED lamp (as to a lamp holder orsocket). And the fuses F1 and F2 perform protection when an electricalcurrent conducted through the LED lamp is excessive, to prevent anexcessive current from damaging (electrical circuits in) the LED lamp.

If an AC signal is coupled/input across the pins A1 and A2 to provide asingle-end power supply to an LED tube lamp, meaning the AC signal isprovided across the pins A1 and A2 on one of the two ends of the lamptube of the LED tube lamp, a current from the AC signal flows from oneof the two pins A1 and A2 into the LED tube lamp, and then flows out ofthe LED tube lamp from the other of the two pins A1 and A2.

On the other hand, if an AC signal is coupled/input across the two endsof the LED tube lamp, meaning the AC signal is coupled to one of pins A1and A2 and one of pins B1 and B2 to provide a double-end power supply tothe LED tube lamp, then a current from the AC signal flows from one ofthe two pins A1 and A2 (or one of the two pins B1 and B2) into the LEDtube lamp, and then flows out of the LED tube lamp from one of the twopins B1 and B2 (or one of the two pins A1 and A2) at the other end ofthe LED tube lamp. Putting this differently, during the connected ACsignal's positive half cycle, the current from the AC signal may flowthrough the first pin A1 and the diode D1 of the rectifying unit 110, orthrough the second pin A2 and the diode D3 of the rectifying unit 110,into the LED tube lamp, then flow through the filtering circuit 120 andthe LED (lighting) module 130, and then flow through the diode D6 of thecompatible circuit 140, the capacitor C3, and finally through the fuseF1 and the third pin B1, or fuse F2 and the fourth pin B2, out of theLED tube lamp. And during the connected AC signal's negative half cycle,the current from the AC signal may flow through the third pin B1 and thefuse F1, or through the fourth pin B2 and the fuse F2, into the LED tubelamp, then flow through the capacitor C3, the diode D5, the filteringcircuit 120 and the LED (lighting) module 130, and finally through thediode D2 of the rectifying unit 110 and the first pin A1, or the diodeD4 of the rectifying unit 110 and the second pin A2, out of the LED tubelamp.

FIG. 27A is a block diagram of the filtering circuit according to anembodiment of the present invention. A rectifying circuit 510 is shownin FIG. 27A for illustrating its connection with other components,without intending a filtering circuit 520 to include the rectifyingcircuit 510. Referring to FIG. 27A, the filtering circuit 520 includes afiltering unit 523 coupled to two rectifying output terminals 511 and512 to receive and to filter out ripples of a rectified signal from therectifying circuit 510. Accordingly, the waveform of a filtered signalis smoother than that of the rectified signal. The filtering circuit 520may further include another filtering unit 524 coupled between arectifying circuit and a pin correspondingly, for example, between therectifying circuit 510 and the pin 501, the rectifying circuit 510 andthe pin 502, the rectifying circuit 540 and the pin 503, and/or therectifying circuit 540 and the pin 504. The filtering unit 524 is usedto filter a specific frequency, for example, to filter out a specificfrequency of an external driving signal. In this embodiment, thefiltering unit 524 is coupled between the rectifying circuit 510 and thepin 501. The filtering circuit 520 may further include another filteringunit 525 coupled between one of the pins 501 and 502 and one of thediodes of the rectifying circuit 510, or between one of the pins 503 and504 and one of the diodes of the rectifying circuit 540 to reduce orfilter out electromagnetic interference (EMI). In this embodiment, thefiltering unit 525 is coupled between the pin 501 and one of diodes ofthe rectifying circuit 510 (not shown in FIG. 27A). Since the filteringunits 524 and 525 may be present or omitted depending on actualcircumstances of their uses, they are depicted by a dotted line in FIG.27A.

FIG. 27B is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 27B, a filteringunit 623 includes a capacitor 625 having an end coupled to the outputterminal 511 and a filtering output terminal 521 and the other endthereof coupled to the output terminal 512 and a filtering outputterminal 522, and is configured to low-pass filter a rectified signalfrom the output terminals 511 and 512, so as to filter outhigh-frequency components of the rectified signal and thereby output afiltered signal at the filtering output terminals 521 and 522.

FIG. 27C is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 27C, a filteringunit 723 includes a pi filter circuit including a capacitor 725, aninductor 726, and a capacitor 727. As is well known, a pi filter circuitlooks like the symbol π in its shape or structure. The capacitor 725 hasan end connected to the output terminal 511 and coupled to the filteringoutput terminal 521 through the inductor 726, and has another endconnected to the output terminal 512 and the filtering output terminal522. The inductor 726 is coupled between output terminal 511 and thefiltering output terminal 521. The capacitor 727 has an end connected tothe filtering output terminal 521 and coupled to the output terminal 511through the inductor 726, and has another end connected to the outputterminal 512 and the filtering output terminal 522.

As seen between the output terminals 511 and 512 and the filteringoutput terminals 521 and 522, the filtering unit 723 compared to thefiltering unit 623 in FIG. 27B additionally has an inductor 726 and acapacitor 727, which perform the function of low-pass filtering like thecapacitor 725 does. Therefore, the filtering unit 723 in this embodimentcompared to the filtering unit 623 in FIG. 27B has a better ability tofilter out high-frequency components to output a filtered signal with asmoother waveform.

The inductance values of the inductor 726 in the embodiments mentionedabove are chosen in the range of, for example in some embodiments, about10 nH to 10 mH. And the capacitance values of the capacitors 625, 725,and 727 in the embodiments stated above are chosen in the range of, forexample in some embodiments, about 100 pF to 1 uF.

FIG. 27D is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 27D, a filteringunit 824 includes a capacitor 825 and an inductor 828 connected inparallel. The capacitor 825 has an end coupled to the pin 501, and theother end coupled to the output terminal 511, and is configured tohigh-pass filter an external driving signal input at the pin 501 so asto filter out low-frequency components of the external driving signal.The inductor 828 has an end coupled to the pin 501 and the other endcoupled to the output terminal 511, and is configured to low-pass filteran external driving signal input at the pin 501 so as to filter outhigh-frequency components of the external driving signal. Therefore, thecombination of the capacitor 825 and the inductor 828 works to presenthigh impedance to one or more specific frequencies in an externaldriving signal. That is, the parallel-connected capacitor and inductorwork to present a biggest equivalent impedance to a specific frequencyin the external driving signal.

Through appropriately choosing a capacitance value for the capacitor 825and an inductance value for the inductor 828, a center frequency f onthe high-impedance band may be set at a specific value given by

${f = \frac{1}{2\pi\sqrt{LC}}},$where L denotes inductance of the inductor 828 and C denotes capacitanceof the capacitor 825. The center frequency in some embodiments is in therange of about 20-30 kHz, and may be in some cases about 25 kHz. And anLED lamp with filtering unit 824 is able to be certified under safetystandards, for a specific center frequency, as provided by UnderwritersLaboratories (UL).

It's worth noting that the filtering unit 824 may further include aresistor 829 coupled between the pin 501 and the filtering outputterminal 511. In FIG. 27D, the resistor 829 is connected in series tothe parallel-connected capacitor 825 and inductor 828. For example, theresistor 829 may be coupled between the pin 501 and theparallel-connected capacitor 825 and inductor 828, or may be coupledbetween the output terminal 511 and the parallel-connected capacitor 825and inductor 828. In this embodiment, the resistor 829 is coupledbetween the pin 501 and the parallel-connected capacitor 825 andinductor 828. Further, the resistor 829 is configured to adjust thequality factor (Q) of the LC circuit comprising the capacitor 825 andthe inductor 828 to make the filtering unit 824 adapting to applicationenvironments with different quality factor requirements. Since theresistor 829 is an optional component, it is depicted in a dotted linein FIG. 27D.

The capacitance values of the capacitor 825, in some embodiments, are inthe range of about 10 nF-2 uF. The inductance values of the inductor 828are smaller than 2 mH in some embodiments, and may be in some casessmaller than 1 mH. The resistance values of the resistor 829 are biggerthan 50 ohms in some embodiments, and may be in some cases bigger than500 ohms.

In addition to the filtering circuits shown and described in the aboveembodiments, the traditional low-pass or band-pass filters can also beused as the filtering unit in the filtering circuit for the presentinvention.

FIG. 27E is a schematic diagram of the filtering unit according to anembodiment of the present invention. Referring to FIG. 27E, in thisembodiment, a filtering unit 925 is disposed in the rectifying circuit610 as shown in FIG. 25A, and is configured for reducing the EMI(Electromagnetic interference) caused by the rectifying circuit 610and/or other circuits. In this embodiment, the filtering unit 925includes an EMI-reducing capacitor coupled between the pin 501 and theanode of the rectifying diode 614, and also between the pin 502 and theanode of the rectifying diode 613 to reduce the EMI associated with thepositive half cycle of the AC driving signal received at the pins 501and 502. The EMI-reducing capacitor of the filtering unit 925 is alsocoupled between the pin 501 and the cathode of the rectifying diode 612,and between the pin 502 and the cathode of the rectifying diode 611 toreduce the EMI associated with the negative half cycle of the AC drivingsignal received at the pins 501 and 502. In some embodiments, therectifying circuit 610 includes a full-wave bridge rectifier circuitincluding four rectifying diodes 611, 612, 613, and 614. The full-wavebridge rectifier circuit has a first filtering node connecting the anodeof the diode 613 and the cathode of the diode 611, and a secondfiltering node connecting the anode of the diode 614 and the cathode ofthe diode 612. And the EMI-reducing capacitor of the filtering unit 925is coupled between the first filtering node and the second filteringnode.

Similarly, with reference to FIGS. 25C and 26A-C, any capacitor in eachof the circuits in FIGS. 26A-C is coupled between the pins 501 and 502(or the pins 503 and 504) and any diode in FIG. 25C, so any or eachcapacitor in FIGS. 26A-C can work as an EMI-reducing capacitor toachieve the function of reducing EMI. For example, the rectifyingcircuit 510 in FIG. 24B may include a half-wave rectifier circuitincluding two rectifying diodes and having a half-wave node respectivelyconnecting an anode and a cathode of the two rectifying diodes, and anyor each capacitor in FIGS. 26A-C may be coupled between the half-wavenode and at least one of the pins 501 and 502. And the rectifyingcircuit 540 in FIG. 24B may include a half-wave rectifier circuitincluding two rectifying diodes and having a half-wave node respectivelyconnecting an anode and a cathode of the two rectifying diodes, and anyor each capacitor in FIGS. 26A-C may be coupled between the half-wavenode and at least one of the pins 503 and 504.

However, the filtering unit 925 coupled between the pins 501 and 502 isequal to make them short. Referring to FIGS. 26A-C with the state of thefiltering unit 925 making the pins 501 and 502 short, one of thecapacitors 645, 646, 745, 746, 845, and 846 in each correspondingembodiment can be ignored. In spite of the external AC signal beingoutput from the pin 501 or 502, the voltage-divided function still canbe achieved after omitting one of the capacitors 645, 646, 745, 746,845, and 846 in each corresponding embodiment.

It's worth noting that the EMI-reducing capacitor in the embodiment ofFIG. 27E may also act as the capacitor 825 in the filtering unit 824shown in FIG. 27D, in combination with the inductor 828, to achieve thefunctions of reducing EMI and presenting high impedance to an externaldriving signal at specific frequencies simultaneously. For example, whenthe rectifying circuit includes a full-wave bridge rectifier circuit,the capacitor 825 of the filtering unit 824 may be coupled between thefirst filtering node and the second filtering node of the full-wavebridge rectifier circuit. When the rectifying circuit includes ahalf-wave rectifier circuit, the capacitor 825 of the filtering unit 824may be coupled between the half-wave node of the half-wave rectifiercircuit and at least one of the pins 501 and 502.

FIG. 28A is a schematic diagram of an LED module according to anembodiment of the present invention. Referring to FIG. 28A, an LEDmodule 630 has an anode connected to a filtering output terminal 521, acathode connected to a filtering output terminal 522, and includes atleast one LED unit 632, such as the light source mentioned above. Whentwo or more LED units are included, they are connected in parallel. Theanode of each LED unit 632 is connected to the anode of LED module 630to couple with the filtering output terminal 521, and the cathode ofeach LED unit 632 is connected to the cathode of LED module 630 tocouple to the filtering output terminal 522. Each LED unit 632 includesat least one LED 631. When multiple LEDs 631 are included in an LED unit632, they are connected in series with the anode of the first LED 631connected to the anode of this LED unit 632 and the cathode of the firstLED 631 connected to the next or second LED 631. And the anode of thelast LED 631 in this LED unit 632 is connected to the cathode of aprevious LED 631 and the cathode of the last LED 631 connected to thecathode of this LED unit 632.

It's noticeable that the LED module 630 may produce a current detectionsignal S531 reflecting the magnitude of current through the LED module630 and being used for controlling or detecting the LED module 630.

FIG. 28B is a schematic diagram of an LED module according to anembodiment of the present invention. Referring to FIG. 28B, an LEDmodule 630 has an anode connected to a filtering output terminal 521, acathode connected to a filtering output terminal 522, and includes atleast two LED units 732 with the anode of each LED unit 732 connected tothe anode of LED module 630 and the cathode of each LED unit 732connected to the cathode of LED module 630. Each LED unit 732 includesat least two LEDs 731 connected in the same way as those described inFIG. 28A. For example, the anode of the first LED 731 in an LED unit 732is connected to the anode of this LED unit 732, the cathode of the firstLED 731 is connected to the anode of the next or second LED 731, and thecathode of the last LED 731 is connected to the cathode of this LED unit732. Further, LED units 732 in an LED module 630 are connected to eachother in this embodiment. All of the n-th LEDs 731 in the related LEDunits 732 thereof are connected by their anodes and cathodes, such asthose shown in FIG. 28B but not limit to, where n is a positive integer.In this way, the LEDs in the LED module 630 of this embodiment areconnected in the form of a mesh.

Compared to the embodiments of FIGS. 29A-G, the LED lighting module 530in the above embodiments includes the LED module 630, but doesn'tinclude a driving circuit for the LED module 630.

Also, the LED module 630 in this embodiment may produce a currentdetection signal S531 reflecting the magnitude of current through theLED module 630 and being used for controlling or detecting the LEDmodule 630.

Besides, in fact, the number of LEDs 731 included by an LED unit 732 insome embodiments is in the range of 15-25, and may be in someembodiments in the range of 18-22.

FIG. 28C is a plan view of a circuit layout of the LED module accordingto an embodiment of the present invention. Referring to FIG. 28C, inthis embodiment, multiple LEDs 831 are connected in the same way asdescribed in FIG. 28B, and three LED units are assumed in the LED module630 and described as follows for illustration. A positive conductiveline 834 and a negative conductive line 835 are to receive a drivingsignal for supplying power to the LEDs 831. For example, the positiveconductive line 834 may be coupled to the filtering output terminal 521of the filtering circuit 520 described above, and the negativeconductive line 835 coupled to the filtering output terminal 522 of thefiltering circuit 520 to receive a filtered signal. For the convenienceof illustration, all three of the n-th LEDs 831 in the three related LEDunits thereof are grouped as an LED set 833 in FIG. 28C.

The positive conductive line 834 connects the three first LEDs 831 ofthe leftmost three related LED units thereof, that is, connects theanodes on the left sides of the three first LEDs 831 as shown in theleftmost LED set 833 of FIG. 28C. The negative conductive line 835connects the three last LEDs 831 of the rightmost three correspondingLED units thereof, that is, connects the cathodes on the right sides ofthe three last LEDs 831 as shown in the rightmost LED set 833 of FIG.28C. The cathodes of the three first LEDs 831, the anodes of the threelast LEDs 831, and the anodes and cathodes of all the remaining LEDs 831are connected by conductive lines or parts 839.

For example, the anodes of the three LEDs 831 in the leftmost LED set833 may be connected together by the positive conductive line 834, andtheir cathodes may be connected together by a leftmost conductive part839. The anodes of the three LEDs 831 in the second leftmost LED set 833are also connected together by the leftmost conductive part 839, whereastheir cathodes are connected together by a second leftmost conductivepart 839. Since the cathodes of the three LEDs 831 in the leftmost LEDset 833 and the anodes of the three LEDs 831 in the second leftmost LEDset 833 are connected together by the same leftmost conductive part 839,the cathode of the first LED 831 in each of the three LED units isconnected to the anode of the next or second LED 831. As for theremaining LEDs 831 are also connected in the same way. Accordingly, allthe LEDs 831 of the three LED units are connected to form the mesh asshown in FIG. 28B.

It's worth noting that, in this embodiment, the length 836 of a portionof each conductive part 839 that connects to the anode of an LED 831 issmaller than the length 837 of another portion of each conductive part839 that connects to the cathode of an LED 831. This makes the area ofthe latter portion connecting to the cathode larger than that of theformer portion connecting to the anode. Moreover, the length 837 may besmaller than a length 838 of a portion of each conductive part 839 thatconnects the cathode of an LED 831 and the anode of the next LED 831 intwo adjacent LED sets 833. This makes the area of the portion of eachconductive part 839 that connects a cathode and an anode larger than thearea of any other portion of each conductive part 839 that connects toonly a cathode or an anode of an LED 831. Due to the length differencesand area differences, this layout structure improves heat dissipation ofthe LEDs 831.

In some embodiments, the positive conductive line 834 includes alengthwise portion 834 a, and the negative conductive line 835 includesa lengthwise portion 835 a, which are conducive to make the LED modulehave a positive “+” connective portion and a negative “−” connectiveportion at each of the two ends of the LED module, as shown in FIG. 28C.Such a layout structure allows for coupling any of other circuits of thepower supply module of the LED lamp, including e.g. the filteringcircuit 520 and the rectifying circuits 510 and 540, to the LED modulethrough the positive connective portion and/or the negative connectiveportion at each or both ends of the LED lamp. Thus the layout structureincreases the flexibility in arranging actual circuits in the LED lamp.

FIG. 28D is a plan view of a circuit layout of the LED module accordingto another embodiment of the present invention. Referring to FIG. 28D,in this embodiment, multiple LEDs 931 are connected in the same way asdescribed in FIG. 28A, and three LED units each including 7 LEDs 931 areassumed in the LED module 630 and described as follows for illustration.A positive conductive line 934 and a negative conductive line 935 are toreceive a driving signal for supplying power to the LEDs 931. Forexample, the positive conductive line 934 may be coupled to thefiltering output terminal 521 of the filtering circuit 520 describedabove, and the negative conductive line 935 is coupled to the filteringoutput terminal 522 of the filtering circuit 520, so as to receive afiltered signal. For the convenience of illustration, all seven LEDs 931of each of the three LED units are grouped as an LED set 932 in FIG.28D. Thus there are three LED sets 932 corresponding to the three LEDunits.

The positive conductive line 934 connects the anode on the left side ofthe first or leftmost LED 931 of each of the three LED sets 932. Thenegative conductive line 935 connects the cathode on the right side ofthe last or rightmost LED 931 of each of the three LED sets 932. In eachLED set 932 of each two adjacent LEDs 931, the LED 931 on the left has acathode connected by a conductive part 939 to an anode of the LED 931 onthe right. By such a layout, the LEDs 931 of each LED set 932 areconnected in series.

It's also worth noting that the conductive part 939 may be used toconnect an anode and a cathode of two consecutive LEDs 931 respectively.The negative conductive line 935 connects the cathode of the last orrightmost LED 931 of each of the three LED sets 932. And the positiveconductive line 934 connects the anode of the first or leftmost LED 931of each of the three LED sets 932. Therefore, as shown in FIG. 28D, thelength of the conductive part 939 is larger than that of the portion ofnegative conductive line 935 connecting to a cathode, which length isthen larger than that of the portion of positive conductive line 934connecting to an anode. For example, the length 938 of the conductivepart 939 may be larger than the length 937 of the portion of negativeconductive line 935 connecting a cathode of an LED 931, which length 937is then larger than the length 936 of the portion of the positiveconductive line 934 connecting an anode of an LED 931. Such a layoutstructure improves heat dissipation of the LEDs 931 in LED module 630.

The positive conductive line 934 may include a lengthwise portion 934 a,and the negative conductive line 935 may include a lengthwise portion935 a, which are conducive to make the LED module have a positive “+”connective portion and a negative “−” connective portion at each of thetwo ends of the LED module, as shown in FIG. 28D. Such a layoutstructure allows for coupling any of other circuits of the power supplymodule of the LED lamp, including e.g. the filtering circuit 520 and therectifying circuits 510 and 540, to the LED module through the positiveconnective portion 934 a and/or the negative connective portion 935 a ateach or both ends of the LED lamp. Thus the layout structure increasesthe flexibility in arranging actual circuits in the LED lamp.

Further, the circuit layouts as shown in FIGS. 28C and 28D may beimplemented with a bendable circuit sheet or substrate, which may evenbe called flexible circuit board depending on its specific definitionused. For example, the bendable circuit sheet may comprise oneconductive layer where the positive conductive line 834, the positivelengthwise portion 834 a, the negative conductive line 835, the negativelengthwise portion 835 a, and the conductive parts 839 shown in FIG.28C, and the positive conductive line 934, the positive lengthwiseportion 934 a, the negative conductive line 935, the negative lengthwiseportion 935 a, and the conductive parts 939 shown in FIG. 28D are formedby the method of etching.

FIG. 28E is a plan view of a circuit layout of the LED module accordingto another embodiment of the present invention. The layout structures ofthe LED module in FIGS. 28E and 28C correspond to the same way ofconnecting the LEDs 831 as those shown in FIG. 28B, but the layoutstructure in FIG. 28E comprises two conductive layers instead of onlyone conductive layer for forming the circuit layout as shown in FIG.28C. Referring to FIG. 28E, the main difference from the layout in FIG.28C is that the positive conductive line 834 and the negative conductiveline 835 have a lengthwise portion 834 a and a lengthwise portion 835 a,respectively, that are formed in a second conductive layer instead. Thedifference is elaborated as follows.

Referring to FIGS. 28E and 23, the bendable circuit sheet of the LEDmodule comprises a first conductive layer 2 a and a second conductivelayer 2 c electrically insulated from each other by a dielectric layer 2b (not shown). Of the two conductive layers, the positive conductiveline 834, the negative conductive line 835, and the conductive parts 839in FIG. 28E are formed in first conductive layer 2 a by the method ofetching for electrically connecting the plurality of LED components 831e.g. in a form of a mesh, whereas the positive lengthwise portion 834 aand the negative lengthwise portion 835 a are formed in secondconductive layer 2 c by etching for electrically connecting (thefiltering output terminal of) the filtering circuit. Further, thepositive conductive line 834 and the negative conductive line 835 in thefirst conductive layer 2 a have via points 834 b and via points 835 b,respectively, for connecting to second conductive layer 2 c. And thepositive lengthwise portion 834 a and the negative lengthwise portion835 a in second conductive layer 2 c have via points 834 c and viapoints 835 c, respectively. The via points 834 b are positionedcorresponding to the via points 834 c, for connecting the positiveconductive line 834 and the positive lengthwise portion 834 a. The viapoints 835 b are positioned corresponding to the via points 835 c, forconnecting the negative conductive line 835 and the negative lengthwiseportion 835 a. An exemplary desirable way of connecting the twoconductive layers is to form a hole connecting each via point 834 b anda corresponding via point 834 c, and to form a hole connecting each viapoint 835 b and a corresponding via point 835 c, with the holesextending through the two conductive layers and the dielectric layerin-between. And the positive conductive line 834 and the positivelengthwise portion 834 a can be electrically connected by weldingmetallic part(s) through the connecting hole(s), and the negativeconductive line 835 and the negative lengthwise portion 835 a can beelectrically connected by welding metallic part(s) through theconnecting hole(s).

Similarly, the layout structure of the LED module in FIG. 28D mayalternatively have the positive lengthwise portion 934 a and thenegative lengthwise portion 935 a disposed in a second conductive layerto constitute a two-layered layout structure.

It's worth noting that the thickness of the second conductive layer of atwo-layered bendable circuit sheet is, in some embodiments, larger thanthat of the first conductive layer in order to reduce the voltage dropor loss along each of the positive lengthwise portion and the negativelengthwise portion disposed in the second conductive layer. Compared toa one-layered bendable circuit sheet, since a positive lengthwiseportion and a negative lengthwise portion are disposed in a secondconductive layer in a two-layer bendable circuit sheet, the width(between two lengthwise sides) of the two-layered bendable circuit sheetis or can be reduced. On the same fixture or plate in a productionprocess, the number of bendable circuit sheets each with a shorter widththat can be laid together at most is larger than the number of bendablecircuit sheets each with a longer width that can be laid together atmost. Thus adopting a bendable circuit sheet with a shorter width canincrease the efficiency of production of the LED module. And reliabilityin the production process, such as the accuracy of welding position whenwelding (materials on) the LED components, can also be improved, becausea two-layer bendable circuit sheet can better maintain its shape.

As a variant of the above embodiments, a type of LED tube lamp isprovided that has at least some of the electronic components of itspower supply module disposed on a light strip of the LED tube lamp. Forexample, the technique of printed electronic circuit (PEC) can be usedto print, insert, or embed at least some of the electronic componentsonto the light strip.

In one embodiment, all electronic components of the power supply moduleare disposed on the light strip. The production process may include orproceed with the following steps: preparation of the circuit substrate(e.g. preparation of a flexible printed circuit board); ink jet printingof metallic nano-ink; ink jet printing of active and passive components(as of the power supply module); drying/sintering; ink jet printing ofinterlayer bumps; spraying of insulating ink; ink jet printing ofmetallic nano-ink; ink jet printing of active and passive components (tosequentially form the included layers); spraying of surface bond pad(s);and spraying of solder resist against LED components.

In certain embodiments, if all electronic components of the power supplymodule are disposed on the LED light strip, electrical connectionbetween the terminal pins of the LED tube lamp and the light strip maybe achieved by connecting the pins to conductive lines which are weldedwith ends of the light strip. In this case, another substrate forsupporting the power supply module is not required, thereby allowing ofan improved design or arrangement in the end cap(s) of the LED tubelamp. In some embodiments, (components of) the power supply module aredisposed at two ends of the light strip, in order to significantlyreduce the impact of heat generated from the power supply module'soperations on the LED components. Since no substrate other than thelight strip is used to support the power supply module in this case, thetotal amount of welding or soldering can be significantly reduced,improving the general reliability of the power supply module.

Another case is that some of all electronic components of the powersupply module, such as some resistors and/or smaller size capacitors,are printed onto the light strip, and some bigger size components, suchas some inductors and/or electrolytic capacitors, are disposed in theend cap(s). The production process of the light strip in this case maybe the same as that described above. And in this case disposing some ofall electronic components on the light strip is conducive to achieving areasonable layout of the power supply module in the LED tube lamp, whichmay allow of an improved design in the end cap(s).

As a variant embodiment of the above, electronic components of the powersupply module may be disposed on the LED light strip by a method ofembedding or inserting, e.g. by embedding the components onto a bendableor flexible light strip. In some embodiments, this embedding may berealized by a method using copper-clad laminates (CCL) for forming aresistor or capacitor; a method using ink related to silkscreenprinting; or a method of ink jet printing to embed passive components,wherein an ink jet printer is used to directly print inks to constitutepassive components and related functionalities to intended positions onthe light strip. Then through treatment by ultraviolet (UV) light ordrying/sintering, the light strip is formed where passive components areembedded. The electronic components embedded onto the light stripinclude for example resistors, capacitors, and inductors. In otherembodiments, active components also may be embedded. Through embeddingsome components onto the light strip, a reasonable layout of the powersupply module can be achieved to allow of an improved design in the endcap(s), because the surface area on a printed circuit board used forcarrying components of the power supply module is reduced or smaller,and as a result the size, weight, and thickness of the resulting printedcircuit board for carrying components of the power supply module is alsosmaller or reduced. Also in this situation since welding points on theprinted circuit board for welding resistors and/or capacitors if theywere not to be disposed on the light strip are no longer used, thereliability of the power supply module is improved, in view of the factthat these welding points are most liable to (cause or incur) faults,malfunctions, or failures. Further, the length of conductive linesneeded for connecting components on the printed circuit board istherefore also reduced, which allows of a more compact layout ofcomponents on the printed circuit board and thus improving thefunctionalities of these components.

Next, methods to produce embedded capacitors and resistors are explainedas follows.

Usually, methods for manufacturing embedded capacitors employ or involvea concept called distributed or planar capacitance. The manufacturingprocess may include the following step(s). On a substrate of a copperlayer a very thin insulation layer is applied or pressed, which is thengenerally disposed between a pair of layers including a power conductivelayer and a ground layer. The very thin insulation layer makes thedistance between the power conductive layer and the ground layer veryshort. A capacitance resulting from this structure can also be realizedby a conventional technique of a plated-through hole. Basically, thisstep is used to create this structure comprising a big parallel-platecapacitor on a circuit substrate.

Of products of high electrical capacity, certain types of productsemploy distributed capacitances, and other types of products employseparate embedded capacitances. Through putting or adding a highdielectric-constant material, such as barium titanate, into theinsulation layer, the high electrical capacity is achieved.

A usual method for manufacturing embedded resistors employ conductive orresistive adhesive. This may include, for example, a resin to whichconductive carbon or graphite is added, which may be used as an additiveor filler. The additive resin is silkscreen printed to an objectlocation, and is then after treatment laminated inside the circuitboard. The resulting resistor is connected to other electroniccomponents through plated-through holes or microvias. Another method iscalled Ohmega-Ply, by which a two metallic layer structure of a copperlayer and a thin nickel alloy layer constitutes a layer resistorrelative to a substrate. Then through etching the copper layer andnickel alloy layer, different types of nickel alloy resistors withcopper terminals can be formed. These types of resistor are eachlaminated inside the circuit board.

In an embodiment, conductive wires/lines are directly printed in alinear layout on an inner surface of the LED glass lamp tube, with LEDcomponents directly attached on the inner surface and electricallyconnected by the conductive wires. In some embodiments, the LEDcomponents in the form of chips are directly attached over theconductive wires on the inner surface, and connective points are atterminals of the wires for connecting the LED components and the powersupply module. After being attached, the LED chips may have fluorescentpowder applied or dropped thereon, for producing white light or light ofother color by the operating LED tube lamp.

In some embodiments, luminous efficacy of the LED or LED component is 80lm/W or above, and in some embodiments, it may be 120 lm/W or above.Certain more optimal embodiments may include a luminous efficacy of theLED or LED component of 160 lm/W or above. White light emitted by an LEDcomponent in the invention may be produced by mixing fluorescent powderwith the monochromatic light emitted by a monochromatic LED chip. Thewhite light in its spectrum has major wavelength ranges of 430-460 nmand 550-560 nm, or major wavelength ranges of 430-460 nm, 540-560 nm,and 620-640 nm.

FIG. 29A is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. As shown in FIG.29A, the power supply module of the LED lamp includes two rectifyingcircuits 510 and 540, a filtering circuit 520, and a driving circuit1530. In this embodiment, a driving circuit 1530 and an LED module 630compose the LED lighting module 530. The driving circuit 1530 comprisesa DC-to-DC converter circuit, and is coupled to the filtering outputterminals 521 and 522 to receive a filtered signal and then performpower conversion for converting the filtered signal into a drivingsignal at the driving output terminals 1521 and 1522. The LED module 630is coupled to the driving output terminals 1521 and 1522 to receive thedriving signal for emitting light. In some embodiments, the current ofLED module 630 is stabilized at an objective current value. Descriptionsof this LED module 630 are the same as those provided above withreference to FIGS. 28A-D.

FIG. 29B is a block diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 29B, a drivingcircuit includes a controller 1531, and a conversion circuit 1532 forpower conversion based on a current source, for driving the LED moduleto emit light. The conversion circuit 1532 includes a switching circuit1535 and an energy storage circuit 1538. And the conversion circuit 1532is coupled to the filtering output terminals 521 and 522 to receive andthen convert a filtered signal, under the control by the controller1531, into a driving signal at the driving output terminals 1521 and1522 for driving the LED module. Under the control by the controller1531, the driving signal output by the conversion circuit 1532 comprisesa steady current, making the LED module emitting steady light.

FIG. 29C is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 29C, a drivingcircuit 1630 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 1631 and a converter circuit. The convertercircuit includes an inductor 1632, a diode 1633 for “freewheeling” ofcurrent, a capacitor 1634, and a switch 1635. The driving circuit 1630is coupled to the filtering output terminals 521 and 522 to receive andthen convert a filtered signal into a driving signal for driving an LEDmodule connected between the driving output terminals 1521 and 1522.

In this embodiment, the switch 1635 comprises ametal-oxide-semiconductor field-effect transistor (MOSFET) and has afirst terminal coupled to the anode of freewheeling diode 1633, a secondterminal coupled to the filtering output terminal 522, and a controlterminal coupled to the controller 1631 used for controlling currentconduction or cutoff between the first and second terminals of switch1635. The driving output terminal 1521 is connected to the filteringoutput terminal 521, and the driving output terminal 1522 is connectedto an end of the inductor 1632, which has another end connected to thefirst terminal of switch 1635. The capacitor 1634 is coupled between thedriving output terminals 1521 and 1522 to stabilize the voltage betweenthe driving output terminals 1521 and 1522. The freewheeling diode 1633has a cathode connected to the driving output terminal 1521.

Next, a description follows as to an exemplary operation of the drivingcircuit 1630.

The controller 1631 is configured for determining when to turn theswitch 1635 on (in a conducting state) or off (in a cutoff state)according to a current detection signal S535 and/or a current detectionsignal S531. For example, in some embodiments, the controller 1631 isconfigured to control the duty cycle of switch 1635 being on and switch1635 being off in order to adjust the size or magnitude of the drivingsignal. The current detection signal S535 represents the magnitude ofcurrent through the switch 1635. The current detection signal S531represents the magnitude of current through the LED module coupledbetween the driving output terminals 1521 and 1522. According to any ofcurrent detection signal S535 and current detection signal S531, thecontroller 1631 can obtain information on the magnitude of powerconverted by the converter circuit. When the switch 1635 is switched on,a current of a filtered signal is input through the filtering outputterminal 521, and then flows through the capacitor 1634, the drivingoutput terminal 1521, the LED module, the inductor 1632, and the switch1635, and then flows out from the filtering output terminal 522. Duringthis flowing of current, the capacitor 1634 and the inductor 1632 areperforming storing of energy. On the other hand, when the switch 1635 isswitched off, the capacitor 1634 and the inductor 1632 perform releasingof stored energy by a current flowing from the freewheeling diode 1633to the driving output terminal 1521 to make the LED module continuing toemit light.

It's worth noting that the capacitor 1634 is an optional element, so itcan be omitted and is thus depicted in a dotted line in FIG. 29C. Insome application environments, the natural characteristic of an inductorto oppose instantaneous change in electric current passing through theinductor may be used to achieve the effect of stabilizing the currentthrough the LED module, thus omitting the capacitor 1634.

FIG. 29D is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 29D, a drivingcircuit 1730 in this embodiment comprises a boost DC-to-DC convertercircuit having a controller 1731 and a converter circuit. The convertercircuit includes an inductor 1732, a diode 1733 for “freewheeling” ofcurrent, a capacitor 1734, and a switch 1735. The driving circuit 1730is configured to receive and then convert a filtered signal from thefiltering output terminals 521 and 522 into a driving signal for drivingan LED module coupled between the driving output terminals 1521 and1522.

The inductor 1732 has an end connected to the filtering output terminal521, and another end connected to the anode of freewheeling diode 1733and a first terminal of the switch 1735, which has a second terminalconnected to the filtering output terminal 522 and the driving outputterminal 1522. The freewheeling diode 1733 has a cathode connected tothe driving output terminal 1521. And the capacitor 1734 is coupledbetween the driving output terminals 1521 and 1522.

The controller 1731 is coupled to a control terminal of switch 1735, andis configured for determining when to turn the switch 1735 on (in aconducting state) or off (in a cutoff state), according to a currentdetection signal S535 and/or a current detection signal S531. When theswitch 1735 is switched on, a current of a filtered signal is inputthrough the filtering output terminal 521, and then flows through theinductor 1732 and the switch 1735, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 1732 increases with time, with the inductor 1732 being in astate of storing energy, while the capacitor 1734 enters a state ofreleasing energy, making the LED module continuing to emit light. On theother hand, when the switch 1735 is switched off, the inductor 1732enters a state of releasing energy as the current through the inductor1732 decreases with time. In this state, the current through theinductor 1732 then flows through the freewheeling diode 1733, thecapacitor 1734, and the LED module, while the capacitor 1734 enters astate of storing energy.

It's worth noting that the capacitor 1734 is an optional element, so itcan be omitted and is thus depicted in a dotted line in FIG. 29D. Whenthe capacitor 1734 is omitted and the switch 1735 is switched on, thecurrent of inductor 1732 does not flow through the LED module, makingthe LED module not emit light; but when the switch 1735 is switched off,the current of inductor 1732 flows through the freewheeling diode 1733to reach the LED module, making the LED module emit light. Therefore, bycontrolling the time that the LED module emits light, and the magnitudeof current through the LED module, the average luminance of the LEDmodule can be stabilized to be above a defined value, thus alsoachieving the effect of emitting a steady light.

FIG. 29E is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 29E, a drivingcircuit 1830 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 1831 and a converter circuit. The convertercircuit includes an inductor 1832, a diode 1833 for “freewheeling” ofcurrent, a capacitor 1834, and a switch 1835. The driving circuit 1830is coupled to the filtering output terminals 521 and 522 to receive andthen convert a filtered signal into a driving signal for driving an LEDmodule connected between the driving output terminals 1521 and 1522.

The switch 1835 has a first terminal coupled to the filtering outputterminal 521, a second terminal coupled to the cathode of freewheelingdiode 1833, and a control terminal coupled to the controller 1831 toreceive a control signal from the controller 1831 for controllingcurrent conduction or cutoff between the first and second terminals ofthe switch 1835. The anode of freewheeling diode 1833 is connected tothe filtering output terminal 522 and the driving output terminal 1522.The inductor 1832 has an end connected to the second terminal of switch1835, and another end connected to the driving output terminal 1521. Thecapacitor 1834 is coupled between the driving output terminals 1521 and1522 to stabilize the voltage between the driving output terminals 1521and 1522.

The controller 1831 is configured for controlling when to turn theswitch 1835 on (in a conducting state) or off (in a cutoff state)according to a current detection signal S535 and/or a current detectionsignal S531. When the switch 1835 is switched on, a current of afiltered signal is input through the filtering output terminal 521, andthen flows through the switch 1835, the inductor 1832, and the drivingoutput terminals 1521 and 1522, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 1832 and the voltage of the capacitor 1834 both increasewith time, so the inductor 1832 and the capacitor 1834 are in a state ofstoring energy. On the other hand, when the switch 1835 is switched off,the inductor 1832 is in a state of releasing energy and thus the currentthrough it decreases with time. In this case, the current through theinductor 1832 circulates through the driving output terminals 1521 and1522, the freewheeling diode 1833, and back to the inductor 1832.

It's worth noting that the capacitor 1834 is an optional element, so itcan be omitted and is thus depicted in a dotted line in FIG. 29E. Whenthe capacitor 1834 is omitted, no matter whether the switch 1835 isturned on or off, the current through the inductor 1832 will flowthrough the driving output terminals 1521 and 1522 to drive the LEDmodule to continue emitting light.

FIG. 29F is a schematic diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 29F, a drivingcircuit 1930 in this embodiment comprises a buck DC-to-DC convertercircuit having a controller 1931 and a converter circuit. The convertercircuit includes an inductor 1932, a diode 1933 for “freewheeling” ofcurrent, a capacitor 1934, and a switch 1935. The driving circuit 1930is coupled to the filtering output terminals 521 and 522 to receive andthen convert a filtered signal into a driving signal for driving an LEDmodule connected between the driving output terminals 1521 and 1522.

The inductor 1932 has an end connected to the filtering output terminal521 and the driving output terminal 1522, and another end connected to afirst end of the switch 1935. The switch 1935 has a second end connectedto the filtering output terminal 522, and a control terminal connectedto controller 1931 to receive a control signal from controller 1931 forcontrolling current conduction or cutoff of the switch 1935. Thefreewheeling diode 1933 has an anode coupled to a node connecting theinductor 1932 and the switch 1935, and a cathode coupled to the drivingoutput terminal 1521. The capacitor 1934 is coupled to the drivingoutput terminals 1521 and 1522 to stabilize the driving of the LEDmodule coupled between the driving output terminals 1521 and 1522.

The controller 1931 is configured for controlling when to turn theswitch 1935 on (in a conducting state) or off (in a cutoff state)according to a current detection signal S531 and/or a current detectionsignal S535. When the switch 1935 is turned on, a current is inputthrough the filtering output terminal 521, and then flows through theinductor 1932 and the switch 1935, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 1932 increases with time, so the inductor 1932 is in astate of storing energy; but the voltage of the capacitor 1934 decreaseswith time, so the capacitor 1934 is in a state of releasing energy tokeep the LED module continuing to emit light. On the other hand, whenthe switch 1935 is turned off, the inductor 1932 is in a state ofreleasing energy and its current decreases with time. In this case, thecurrent through the inductor 1932 circulates through the freewheelingdiode 1933, the driving output terminals 1521 and 1522, and back to theinductor 1932. During this circulation, the capacitor 1934 is in a stateof storing energy and its voltage increases with time.

It's worth noting that the capacitor 1934 is an optional element, so itcan be omitted and is thus depicted in a dotted line in FIG. 29F. Whenthe capacitor 1934 is omitted and the switch 1935 is turned on, thecurrent through the inductor 1932 doesn't flow through the drivingoutput terminals 1521 and 1522, thereby making the LED module not emitlight. On the other hand, when the switch 1935 is turned off, thecurrent through the inductor 1932 flows through the freewheeling diode1933 and then the LED module to make the LED module emit light.Therefore, by controlling the time that the LED module emits light, andthe magnitude of current through the LED module, the average luminanceof the LED module can be stabilized to be above a defined value, thusalso achieving the effect of emitting a steady light.

FIG. 29G is a block diagram of the driving circuit according to anembodiment of the present invention. Referring to FIG. 29G, the drivingcircuit includes a controller 2631, and a conversion circuit 2632 forpower conversion based on an adjustable current source, for driving theLED module to emit light. The conversion circuit 2632 includes aswitching circuit 2635 and an energy storage circuit 2638. And theconversion circuit 2632 is coupled to the filtering output terminals 521and 522 to receive and then convert a filtered signal, under the controlby the controller 2631, into a driving signal at the driving outputterminals 1521 and 1522 for driving the LED module. The controller 2631is configured to receive a current detection signal S535 and/or acurrent detection signal S539 for controlling or stabilizing the drivingsignal output by the conversion circuit 2632 to be above an objectivecurrent value. The current detection signal S535 represents themagnitude of current through the switching circuit 2635. The currentdetection signal S539 represents the magnitude of current through energystorage circuit 2638, which current may be e.g. an inductor current inenergy storage circuit 2638 or a current output at the driving outputterminal 1521. Any of current detection signal S535 and currentdetection signal S539 can represent the magnitude of current Ioutprovided by the driving circuit from the driving output terminals 1521and 1522 to the LED module. The controller 2631 is coupled to thefiltering output terminal 521 for setting the objective current valueaccording to the voltage Vin at the filtering output terminal 521.Therefore, the current Iout provided by the driving circuit or theobjective current value can be adjusted corresponding to the magnitudeof the voltage Vin of a filtered signal output by a filtering circuit.

It's worth noting that current detection signals S535 and S539 can begenerated by measuring current through a resistor or induced by aninductor. For example, a current can be measured according to a voltagedrop across a resistor in the conversion circuit 2632 the current flowsthrough, or which arises from a mutual induction between an inductor inthe conversion circuit 2632 and another inductor in its energy storagecircuit 2638.

The above driving circuit structures are especially suitable for anapplication environment in which the external driving circuit for theLED tube lamp includes electronic ballast. An electronic ballast isequivalent to a current source whose output power is not constant. In aninternal driving circuit as shown in each of FIGS. 29C-F, power consumedby the internal driving circuit relates to or depends on the number ofLEDs in the LED module, and could be regarded as constant. When theoutput power of the electronic ballast is higher than power consumed bythe LED module driven by the driving circuit, the output voltage of theballast will increase continually, causing the logic level of an ACdriving signal received by the power supply module of the LED lamp tocontinually increase, so as to risk damaging the ballast and/orcomponents of the power supply module due to their voltage ratings beingexceeded. On the other hand, when the output power of the electronicballast is lower than power consumed by the LED module driven by thedriving circuit, the output voltage of the ballast and the logic levelof the AC driving signal will decrease continually so that the LED tubelamp fail to normally operate.

It's worth noting that the power needed for an LED lamp to work isalready lower than that needed for a fluorescent lamp to work. If aconventional control mechanism of e.g. using a backlight module tocontrol the LED luminance is used with a conventional driving system ofe.g. a ballast, a problem will probably arise of mismatch orincompatibility between the output power of the external driving systemand the power needed by the LED lamp. This problem may even causedamaging of the driving system and/or the LED lamp. To prevent or reducethis problem, using e.g. the power/current adjustment method describedabove in FIG. 29G enables the LED (tube) lamp to be better compatiblewith traditional fluorescent lighting system.

FIG. 29H is a graph illustrating the relationship between the voltageVin and the objective current value Iout according to an embodiment ofthe present invention. In FIG. 29H, the variable Vin is on thehorizontal axis, and the variable Iout is on the vertical axis. In somecases, when the logic level of the voltage Vin of a filtered signal isbetween the upper voltage limit VH and the lower voltage limit VL, theobjective current value Iout will be about an initial objective currentvalue. The upper voltage limit VH is higher than the lower voltage limitVL. When the voltage Vin increases to be higher than the upper voltagelimit VH, the objective current value Iout will increase with theincreasing of the voltage Vin. During this stage, a situation that maybe preferable is that the slope of the relationship curve increase withthe increasing of the voltage Vin. When the voltage Vin of a filteredsignal decreases to be below the lower voltage limit VL, the objectivecurrent value Iout will decrease with the decreasing of the voltage Vin.During this stage, a situation that may be preferable is that the slopeof the relationship curve decrease with the decreasing of the voltageVin. For example, during the stage when the voltage Vin is higher thanthe upper voltage limit VH or lower than the lower voltage limit VL, theobjective current value Iout is in some embodiments a function of thevoltage Vin to the power of 2 or above, in order to make the rate ofincrease/decrease of the consumed power higher than the rate ofincrease/decrease of the output power of the external driving system.Thus, adjustment of the objective current value Iout is in someembodiments a function of the filtered voltage Vin to the power of 2 orabove.

In another case, when the voltage Vin of a filtered signal is betweenthe upper voltage limit VH and the lower voltage limit VL, the objectivecurrent value Iout of the LED lamp will vary, increase or decrease,linearly with the voltage Vin. During this stage, when the voltage Vinis at the upper voltage limit VH, the objective current value Iout willbe at the upper current limit IH. When the voltage Vin is at the lowervoltage limit VL, the objective current value Iout will be at the lowercurrent limit IL. The upper current limit IH is larger than the lowercurrent limit IL. And when the voltage Vin is between the upper voltagelimit VH and the lower voltage limit VL, the objective current valueIout will be a function of the voltage Vin to the power of 1.

With the designed relationship in FIG. 29H, when the output power of theballast is higher than the power consumed by the LED module driven bythe driving circuit, the voltage Vin will increase with time to exceedthe upper voltage limit VH. When the voltage Vin is higher than theupper voltage limit VH, the rate of increase of the consumed power ofthe LED module is higher than that of the output power of the electronicballast, and the output power and the consumed power will be balanced orequal when the voltage Vin is at a high balance voltage value VH+ andthe current Iout is at a high balance current value IH+. In this case,the high balance voltage value VH+ is larger than the upper voltagelimit VH, and the high balance current value IH+ is larger than theupper current limit IH. On the other hand, when the output power of theballast is lower than the power consumed by the LED module driven by thedriving circuit, the voltage Vin will be below the lower voltage limitVL. When the voltage Vin is lower than the lower voltage limit VL, therate of decrease of the consumed power of the LED module is higher thanthat of the output power of the electronic ballast, and the output powerand the consumed power will be balanced or equal when the voltage Vin isat a low balance voltage value VL− and the objective current value Ioutis at a low balance current value IL−. In this case, the low balancevoltage value VL− is smaller than the lower voltage limit VL, and thelow balance current value IL− is smaller than the lower current limitIL.

In some embodiments, the lower voltage limit VL is defined to be around90% of the lowest output power of the electronic ballast, and the uppervoltage limit VH is defined to be around 110% of its highest outputpower. Taking a common AC powerline with a voltage range of 100-277volts and a frequency of 60 Hz as an example, the lower voltage limit VLmay be set at 90 volts (=100*90%), and the upper voltage limit VH may beset at 305 volts (=277*110%).

With reference to FIGS. 19 and 20, a short circuit board 253 includes afirst short circuit substrate and a second short circuit substraterespectively connected to two terminal portions of a long circuit sheet251, and electronic components of the power supply module arerespectively disposed on the first short circuit substrate and thesecond short circuit substrate. The first short circuit substrate andthe second short circuit substrate may have roughly the same length, ordifferent lengths. In general, the first short circuit substrate (i.e.the right circuit substrate of short circuit board 253 in FIG. 19 andthe left circuit substrate of short circuit board 253 in FIG. 20) has alength that is about 30%-80% of the length of the second short circuitsubstrate (i.e. the left circuit substrate of short circuit board 253 inFIG. 19 and the right circuit substrate of short circuit board 253 inFIG. 20). In some embodiments the length of the first short circuitsubstrate is about ⅓ ˜⅔ of the length of the second short circuitsubstrate. For example, in one embodiment, the length of the first shortcircuit substrate may be about half the length of the second shortcircuit substrate. The length of the second short circuit substrate maybe, for example in the range of about 15 mm to about 65 mm, depending onactual application occasions. In certain embodiments, the first shortcircuit substrate is disposed in an end cap at an end of the LED tubelamp, and the second short circuit substrate is disposed in another endcap at the opposite end of the LED tube lamp.

For example, capacitors of the driving circuit, such as the capacitors1634, 1734, 1834, and 1934 in FIGS. 29C-29F, in practical use mayinclude two or more capacitors connected in parallel. Some or allcapacitors of the driving circuit in the power supply module may bearranged on the first short circuit substrate of short circuit board253, while other components such as the rectifying circuit, filteringcircuit, inductor(s) of the driving circuit, controller(s), switch(es),diodes, etc. are arranged on the second short circuit substrate of shortcircuit board 253. Since the inductors, controllers, switches, etc. areelectronic components with higher temperature, arranging some or allcapacitors on a circuit substrate separate or away from the circuitsubstrate(s) of high-temperature components helps prevent the workinglife of capacitors (especially electrolytic capacitors) from beingnegatively affected by the high-temperature components, thus improvingthe reliability of the capacitors. Further, the physical separationbetween the capacitors and both the rectifying circuit and filteringcircuit also contributes to reducing the problem of EMI.

In some embodiments, the driving circuit has power conversion efficiencyof 80% or above, which may be 90% or above, and may even be 92% orabove. Therefore, without the driving circuit, luminous efficacy of theLED lamp according to some embodiments may be 120 lm/W or above, and mayeven be 160 lm/W or above. On the other hand, with the driving circuitin combination with the LED component(s), luminous efficacy of the LEDlamp in the invention may be, in some embodiments, 120 lm/W*90%=108 lm/Wor above, and may even be, in some embodiments 160 lm/W*92%=147.2 lm/Wor above.

In view of the fact that the diffusion film or layer in an LED tube lamphas light transmittance of 85% or above, luminous efficacy of the LEDtube lamp of the invention is in some embodiments 108 lm/W*85%=91.8 lm/Wor above, and may be, in some more effective embodiments, 147.2lm/W*85%=125.12 lm/W.

FIG. 30A is a block diagram of using a power supply module in an LEDlamp according to an embodiment of the present invention. Compared toFIG. 24B, the embodiment of FIG. 30A includes two rectifying circuits510 and 540, a filtering circuit 520, and a driving circuit 1530, andfurther includes an anti-flickering circuit 550 coupled between thefiltering circuit 520 and the LED lighting module 530. In thisembodiment, a driving circuit 1530 and an LED module 630 compose the LEDlighting module 530.

The anti-flickering circuit 550 is coupled to the filtering outputterminals 521 and 522 to receive a filtered signal, and under specificcircumstances to consume partial energy of the filtered signal so as toreduce (the incidence of) ripples of the filtered signal disrupting orinterrupting the light emission of the LED lighting module 530. Ingeneral, the filtering circuit 520 has such filtering components ascapacitor(s) and/or inductor(s), and/or parasitic capacitors andinductors, which may form resonant circuits. Upon breakoff or stop of anAC power signal, as when the power supply of the LED lamp is turned offby a user, the amplitude(s) of resonant signals in the resonant circuitswill decrease with time. But LEDs in the LED module of the LED lamp areunidirectional conduction devices and generally require a minimumconduction voltage for the LED module. When a resonant signal's troughvalue is lower than the minimum conduction voltage of the LED module,but its peak value is still higher than the minimum conduction voltage,the flickering phenomenon will occur in light emission of the LEDmodule. In this case the anti-flickering circuit 550 works by allowing acurrent matching a defined flickering current value of the LED componentto flow through, consuming partial energy of the filtered signal whichshould be higher than the energy difference of the resonant signalbetween its peak and trough values, so as to reduce the flickeringphenomenon. In certain embodiments, a preferred occasion for theanti-flickering circuit 550 to work is when the filtered signal'svoltage approaches (and is still higher than) the minimum conductionvoltage, and thus the partial energy of the filtered signal consumed bythe anti-flickering circuit 550 is higher than the energy difference ofthe resonant signal between its peak and trough values.

It's worth noting that the anti-flickering circuit 550 may be moresuitable for the situation in which the LED lighting module 530 doesn'tinclude the driving circuit 1530, for example, when the LED module 630of LED lighting module 530 is (directly) driven to emit light by afiltered signal from a filtering circuit. In this case, the lightemission of LED module 630 will directly reflect variation in thefiltered signal due to its ripples. In this situation, the introductionof anti-flickering circuit 550 will prevent the flickering phenomenonfrom occurring in the LED lamp upon the breakoff of power supply to theLED lamp.

FIG. 30B is a schematic diagram of the anti-flickering circuit accordingto an embodiment of the present invention. Referring to FIG. 30B, ananti-flickering circuit 650 includes at least a resistor, such as tworesistors connected in series between the filtering output terminals 521and 522. In this embodiment, the anti-flickering circuit 650 in useconsumes partial energy of a filtered signal continually. When in normaloperation of the LED lamp, this partial energy is far lower than theenergy consumed by LED lighting module 530. But upon a breakoff or stopof the power supply, when the voltage logic level of the filtered signaldecreases to approach the minimum conduction voltage of LED module 630,this partial energy is still consumed by the anti-flickering circuit 650in order to offset the impact of the resonant signals which may causethe flickering of light emission of LED module 630. In some embodiments,a current equal to or larger than an anti-flickering current logic levelmay be set to flow through the anti-flickering circuit 650 when the LEDmodule 630 is supplied by the minimum conduction voltage, and then anequivalent anti-flickering resistance of anti-flickering circuit 650 canbe determined based on the set current.

FIG. 31A is a block diagram of using a power supply module in an LEDlamp according to an embodiment of the present invention. Compared toFIG. 30A, the embodiment of FIG. 31A includes two rectifying circuits510 and 540, a filtering circuit 520, a driving circuit 1530, and ananti-flickering circuit 550, and further includes a protection circuit560. In this embodiment, a driving circuit 1530 and an LED module 630compose the LED lighting module 530. The protection circuit 560 iscoupled to the filtering output terminals 521 and 522 to detect thefiltered signal from the filtering circuit 520 for determining whetherto enter a protection state. Upon entering a protection state, theprotection circuit 560 works to limit, restrain, or clamp down on thelogic level of the filtered signal, preventing damaging of components inthe LED lighting module 530. And the anti-flickering circuit 550 may beomitted and are thus depicted in a dotted line in FIG. 31A.

FIG. 31B is a schematic diagram of the protection circuit according toan embodiment of the present invention. Referring to FIG. 31B, aprotection circuit 660 includes a voltage clamping circuit, a voltagedivision circuit, two capacitors 663 and 670, a resistor 669, and adiode 672, for entering a protection state when a current and/or voltageof the LED module is/are or might be excessively high, thus preventingdamaging of the LED module. The voltage clamping circuit includes abidirectional triode thyristor (TRIAC) 661 and a DIAC or symmetricaltrigger diode 662. The voltage division circuit includes two bipolarjunction transistors (BJT) 667 and 668 and multiple resistors 664, 665,666, and 671.

The bidirectional triode thyristor 661 has a first terminal connected tothe filtering output terminal 521, a second terminal connected to thefiltering output terminal 522, and a control terminal connected to afirst terminal of symmetrical trigger diode 662, which has a secondterminal connected to an end of the capacitor 663, which has another endconnected to the filtering output terminal 522. The resistor 664 is inparallel to the capacitor 663, and has an end connected to the secondterminal of symmetrical trigger diode 662 and another end connected tothe filtering output terminal 522. The resistor 665 has an end connectedto the second terminal of symmetrical trigger diode 662 and another endconnected to the collector terminal of BJT 667, whose emitter terminalis connected to the filtering output terminal 522. The resistor 666 hasan end connected to the second terminal of symmetrical trigger diode 662and another end connected to the collector terminal of BJT 668 and thebase terminal of BJT 667. The emitter terminal of BJT 668 is connectedto the filtering output terminal 522. The resistor 669 has an endconnected to the base terminal of BJT 668 and another end connected toan end of the capacitor 670, which has another end connected to thefiltering output terminal 522. The resistor 671 has an end connected tothe second terminal of symmetrical trigger diode 662 and another endconnected to the cathode of diode 672, whose anode is connected to thefiltering output terminal 521.

It's worth noting that according to some embodiments, the resistance ofresistor 665 should be smaller than that of resistor 666.

Next, an exemplary operation of the protection circuit 660 inovercurrent protection is described as follows.

The node connecting the resistor 669 and the capacitor 670 is to receivea current detection signal S531, which represents the magnitude ofcurrent through the LED module. The other end of the resistor 671 is avoltage terminal 521′. In this embodiment concerning overcurrentprotection, the voltage terminal 521′ may be coupled to a biasingvoltage source, or be connected through the diode 672 to the filteringoutput terminal 521, as shown in FIG. 31B, to take a filtered signal asa biasing voltage source. If the voltage terminal 521′ is coupled to anexternal biasing voltage source, the diode 672 may be omitted, so it isdepicted in a dotted line in FIG. 31B. The combination of the resistor669 and the capacitor 670 can work to filter out high frequencycomponents of the current detection signal S531, and then input thefiltered current detection signal S531 to the base terminal of BJT 668for controlling current conduction and cutoff of the BJT 668. Thefiltering function of the resistor 669 and the capacitor 670 can preventmisoperation of the BJT 668 due to noises. In practical use, theresistor 669 and the capacitor 670 may be omitted, so they are eachdepicted in a dotted line in FIG. 31B. When they are omitted, thecurrent detection signal S531 is input directly to the base terminal ofthe BJT 668.

When the LED lamp is operating normally and the current of the LEDmodule is within a normal range, the BJT 668 is in a cutoff state, andthe resistor 666 works to pull up the base voltage of the BJT 667, whichtherefore enters a conducting state. In this state, the electricpotential at the second terminal of the symmetrical trigger diode 662 isdetermined based on the voltage at the voltage terminal 521′ of thebiasing voltage source and voltage division ratios between the resistor671 and the parallel-connected resistors 664 and 665. Since theresistance of resistor 665 is relatively small, voltage share for theresistor 665 is smaller and the electric potential at the secondterminal of the symmetrical trigger diode 662 is therefore pulled down.Then, the electric potential at the control terminal of thebidirectional triode thyristor 661 is in turn pulled down by thesymmetrical trigger diode 662, causing the bidirectional triodethyristor 661 to enter a cutoff state, which cutoff state makes theprotection circuit 660 not being in a protection state.

When the current of the LED module exceeds an overcurrent value, thelogic level of current detection signal S531 will increase significantlyto cause the BJT 668 to enter a conducting state and then pull down thebase voltage of the BJT 667, which thereby enters a cutoff state. Inthis case, the electric potential at the second terminal of thesymmetrical trigger diode 662 is determined based on the voltage at thevoltage terminal 521′ of the biasing voltage source and voltage divisionratios between the resistor 671 and the parallel-connected resistors 664and 666. Since the resistance of resistor 666 is relatively high,voltage share for the resistor 666 is larger and the electric potentialat the second terminal of symmetrical trigger diode 662 is thereforehigher. Then the electric potential at the control terminal ofbidirectional triode thyristor 661 is in turn pulled up by thesymmetrical trigger diode 662, causing the bidirectional triodethyristor 661 to enter a conducting state, which conducting state worksto restrain or clamp down on the voltage between the filtering outputterminals 521 and 522 and thus makes the protection circuit 660 being ina protection state.

In this embodiment, the voltage at the voltage terminal 521′ of thebiasing voltage source is determined based on the trigger voltage of thebidirectional triode thyristor 661, and voltage division ratio betweenthe resistor 671 and the parallel-connected resistors 664 and 665, orvoltage division ratio between the resistor 671 and theparallel-connected resistors 664 and 666. Through voltage divisionbetween the resistor 671 and the parallel-connected resistors 664 and665, the voltage from the voltage terminal 521′ at the symmetricaltrigger diode 662 will be lower than the trigger voltage of thebidirectional triode thyristor 661. Otherwise, through voltage divisionbetween the resistor 671 and the parallel-connected resistors 664 and666, the voltage from the voltage terminal 521′ at the symmetricaltrigger diode 662 will be higher than the trigger voltage of thebidirectional triode thyristor 661. For example, in some embodiments,when the current of the LED module exceeds an overcurrent value, thevoltage division circuit is adjusted to the voltage division ratiobetween the resistor 671 and the parallel-connected resistors 664 and666, causing a higher portion of the voltage at the voltage terminal521′ to result at the symmetrical trigger diode 662, achieving ahysteresis function. Specifically, the BJTs 667 and 668 as switches arerespectively connected in series to the resistors 665 and 666 whichdetermine the voltage division ratios. The voltage division circuit isconfigured to control turning on which one of the BJTs 667 and 668 andleaving the other off for determining the relevant voltage divisionratio, according to whether the current of the LED module exceeds anovercurrent value. And the clamping circuit determines whether torestrain or clamp down on the voltage of the LED module according to theapplying voltage division ratio.

Next, an exemplary operation of the protection circuit 660 inovervoltage protection is described as follows.

The node connecting the resistor 669 and the capacitor 670 is to receivea current detection signal S531, which represents the magnitude ofcurrent through the LED module. As described above, the protectioncircuit 660 still works to provide overcurrent protection. The other endof resistor 671 is a voltage terminal 521′. In this embodimentconcerning overvoltage protection, the voltage terminal 521′ is coupledto the positive terminal of the LED module to detect the voltage of theLED module. Taking previously described embodiments for example, inembodiments of FIGS. 28A and 28B, the LED lighting module 530 doesn'tinclude the driving circuit 1530, and the voltage terminal 521′ would becoupled to the filtering output terminal 521. Whereas in embodiments ofFIGS. 29A-29G, the LED lighting module 530 includes the driving circuit1530, and the voltage terminal 521′ would be coupled to the drivingoutput terminal 1521. In this embodiment, voltage division ratiosbetween the resistor 671 and the parallel-connected resistors 664 and665, and voltage division ratios between the resistor 671 and theparallel-connected resistors 664 and 666 will be adjusted according tothe voltage at the voltage terminal 521′, for example, the voltage atthe driving output terminal 1521 or the filtering output terminal 521.Therefore, normal overcurrent protection can still be provided by theprotection circuit 660.

In some embodiments, when the LED lamp is operating normally, assumingovercurrent condition doesn't occur, the electric potential at thesecond terminal of the symmetrical trigger diode 662 is determined basedon the voltage at the voltage terminal 521′ and voltage division ratiosbetween the resistor 671 and the parallel-connected resistors 664 and665, and is insufficient to trigger the bidirectional triode thyristor661. Then the bidirectional triode thyristor 661 is in a cutoff state,making the protection circuit 660 not being in a protection state. Onthe other hand, when the LED module is operating abnormally with thevoltage at the positive terminal of the LED module exceeding anovervoltage value, the electric potential at the second terminal ofsymmetrical trigger diode 662 is sufficiently high to trigger thebidirectional triode thyristor 661 when the voltage at the firstterminal of the symmetrical trigger diode 662 is larger than the triggervoltage of the bidirectional triode thyristor 661. Then thebidirectional triode thyristor 661 enters a conducting state, making theprotection circuit 660 being in a protection state to restrain or clampdown on the logic level of the filtered signal.

As described above, the protection circuit 660 provides one or two ofthe functions of overcurrent protection and overvoltage protection.

In some embodiments, the protection circuit 660 may further include azener diode connected to the resistor 664 in parallel, which zener diodeis used to limit or restrain the voltage across the resistor 664. Thebreakdown voltage of the zener diode is in some embodiments in the rangeof about 25-50 volts, and in some embodiments may be about 36 volts.

Further, a silicon controlled rectifier may be substituted for thebidirectional triode thyristor 661, without negatively affecting theprotection functions. Using a silicon controlled rectifier instead of abidirectional triode thyristor 661 has a lower voltage drop acrossitself in conduction than that across the bidirectional triode thyristor661 in conduction.

In one embodiment, values of the parameters of the protection circuit660 may be set as follows. The resistance of resistor 669 may be about10 ohms. The capacitance of capacitor 670 may be about 1 nF. Thecapacitance of capacitor 633 may be about 10 nF. The (breakover) voltageof symmetrical trigger diode 662 may be in the range of about 26-36volts. The resistance of resistor 671 may be in the range of about 300k-600 k ohms, and may be, in some embodiments, about 540 k ohms. Theresistance of resistor 666 is in some embodiments in the range of about100 k-300 k ohms, and may be, in some embodiments, about 220 k ohms. Theresistance of resistor 665 is in some embodiments in the range of about30 k-100 k ohms, and may be, in some embodiments about 40 k ohms. Theresistance of resistor 664 is in some embodiments in the range of about100 k-300 k ohms, and may be, in some embodiments about 220 k ohms.

FIG. 32A is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to FIG.29A, the embodiment of FIG. 32A includes two rectifying circuits 510 and540, a filtering circuit 520, and a driving circuit 1530, and furtherincludes a mode switching circuit 580. In this embodiment, a drivingcircuit 1530 and an LED module 630 compose the LED lighting module 530.The mode switching circuit 580 is coupled to at least one of thefiltering output terminals 521 and 522 and at least one of the drivingoutput terminals 1521 and 1522, for determining whether to perform afirst driving mode or a second driving mode, as according to a frequencyof the external driving signal. In the first driving mode, a filteredsignal from the filtering circuit 520 is input into the driving circuit1530, while in the second driving mode the filtered signal bypasses atleast a component of the driving circuit 1530, making the drivingcircuit 1530 stop working in conducting the filtered signal, allowingthe filtered signal to (directly) reach and drive the LED module 630.The bypassed component(s) of the driving circuit 1530 may include aninductor or a switch, which when bypassed makes the driving circuit 1530unable to transfer and/or convert power, and then stop working inconducting the filtered signal. If the driving circuit 1530 includes acapacitor, the capacitor can still be used to filter out ripples of thefiltered signal in order to stabilize the voltage across the LED module.When the mode switching circuit 580 determines on performing the firstdriving mode, allowing the filtered signal to be input to the drivingcircuit 1530, the driving circuit 1530 then transforms the filteredsignal into a driving signal for driving the LED module 630 to emitlight. On the other hand, when the mode switching circuit 580 determineson performing the second driving mode, allowing the filtered signal tobypass the driving circuit 1530 to reach the LED module 630, thefiltering circuit 520 becomes in effect a driving circuit for LED module630. Then the filtering circuit 520 provides the filtered signal as adriving signal for the LED module for driving the LED module to emitlight.

It's worth noting that the mode switching circuit 580 can determinewhether to perform the first driving mode or the second driving modebased on a user's instruction or a detected signal received by the LEDlamp through the pins 501, 502, 503, and 504. With the mode switchingcircuit, the power supply module of the LED lamp can adapt to or performone of appropriate driving modes corresponding to different applicationenvironments or driving systems, thus improving the compatibility of theLED lamp.

FIG. 32B is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32B, a mode switching circuit 680 includes a mode switch 681suitable for use with the driving circuit 1630 in FIG. 29C. Referring toFIGS. 32B and 29C, the mode switch 681 has three terminals 683, 684, and685, wherein the terminal 683 is coupled to the driving output terminal1522, the terminal 684 is coupled to the filtering output terminal 522,and the terminal 685 is coupled to the inductor 1632 in the drivingcircuit 1630.

When the mode switching circuit 680 determines on performing a firstdriving mode, the mode switch 681 conducts current in a first conductivepath through the terminals 683 and 685 and a second conductive paththrough the terminals 683 and 684 is in a cutoff state. In this case,the driving output terminal 1522 is coupled to the inductor 1632, andtherefore the driving circuit 1630 is working normally, which workingincludes receiving a filtered signal from the filtering output terminals521 and 522 and then transforming the filtered signal into a drivingsignal, output at the driving output terminals 1521 and 1522 for drivingthe LED module.

When the mode switching circuit 680 determines on performing a seconddriving mode, the mode switch 681 conducts current in the secondconductive path through the terminals 683 and 684 and the firstconductive path through the terminals 683 and 685 is in a cutoff state.In this case, the driving output terminal 1522 is coupled to thefiltering output terminal 522, and therefore the driving circuit 1630stops working, and a filtered signal is input through the filteringoutput terminals 521 and 522 to the driving output terminals 1521 and1522 for driving the LED module, while bypassing the inductor 1632 andthe switch 1635 in the driving circuit 1630.

FIG. 32C is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32C, a mode switching circuit 780 includes a mode switch 781 beingsuitable for use with the driving circuit 1630 in FIG. 29C. Referring toFIGS. 32C and 29C, the mode switch 781 has three terminals 783, 784, and785, wherein the terminal 783 is coupled to the filtering outputterminal 522, the terminal 784 is coupled to the driving output terminal1522, and the terminal 785 is coupled to switch 1635 in the drivingcircuit 1630.

When the mode switching circuit 780 determines on performing a firstdriving mode, the mode switch 781 conducts current in a first conductivepath through the terminals 783 and 785 and a second conductive paththrough the terminals 783 and 784 is in a cutoff state. In this case,the filtering output terminal 522 is coupled to the switch 1635, andtherefore the driving circuit 1630 is working normally, which workingincludes receiving a filtered signal from the filtering output terminals521 and 522 and then transforming the filtered signal into a drivingsignal, output at the driving output terminals 1521 and 1522 for drivingthe LED module.

When the mode switching circuit 780 determines on performing a seconddriving mode, the mode switch 781 conducts current in the secondconductive path through the terminals 783 and 784 and the firstconductive path through the terminals 783 and 785 is in a cutoff state.In this case, the driving output terminal 1522 is coupled to thefiltering output terminal 522, and therefore the driving circuit 1630stops working, and a filtered signal is input through the filteringoutput terminals 521 and 522 to the driving output terminals 1521 and1522 for driving the LED module, while bypassing the inductor 1632 andthe switch 1635 in the driving circuit 1630.

FIG. 32D is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32D, a mode switching circuit 880 includes a mode switch 881 beingsuitable for use with the driving circuit 1730 in FIG. 29D. Referring toFIGS. 32D and 29D, the mode switch 881 has three terminals 883, 884, and885, wherein the terminal 883 is coupled to the filtering outputterminal 521, the terminal 884 is coupled to the driving output terminal1521, and the terminal 885 is coupled to the inductor 1732 in thedriving circuit 1730.

When the mode switching circuit 880 determines on performing a firstdriving mode, the mode switch 881 conducts current in a first conductivepath through the terminals 883 and 885 and a second conductive paththrough the terminals 883 and 884 is in a cutoff state. In this case,the filtering output terminal 521 is coupled to the inductor 1732, andtherefore the driving circuit 1730 is working normally, which workingincludes receiving a filtered signal from the filtering output terminals521 and 522 and then transforming the filtered signal into a drivingsignal, output at the driving output terminals 1521 and 1522 for drivingthe LED module.

When the mode switching circuit 880 determines on performing a seconddriving mode, the mode switch 881 conducts current in the secondconductive path through the terminals 883 and 884 and the firstconductive path through the terminals 883 and 885 is in a cutoff state.In this case, the driving output terminal 1521 is coupled to thefiltering output terminal 521, and therefore the driving circuit 1730stops working, and a filtered signal is input through the filteringoutput terminals 521 and 522 to the driving output terminals 1521 and1522 for driving the LED module, while bypassing the inductor 1732 andthe freewheeling diode 1733 in the driving circuit 1730.

FIG. 32E is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32E, a mode switching circuit 980 includes a mode switch 981 beingsuitable for use with the driving circuit 1730 in FIG. 29D. Referring toFIGS. 32E and 29D, the mode switch 981 has three terminals 983, 984, and985, wherein the terminal 983 is coupled to the driving output terminal1521, the terminal 984 is coupled to the filtering output terminal 521,and the terminal 985 is coupled to the cathode of diode 1733 in thedriving circuit 1730.

When the mode switching circuit 980 determines on performing a firstdriving mode, the mode switch 981 conducts current in a first conductivepath through the terminals 983 and 985, and a second conductive paththrough the terminals 983 and 984 is in a cutoff state. In this case,the filtering output terminal 521 is coupled to the cathode of diode1733, and therefore the driving circuit 1730 is working normally, whichworking includes receiving a filtered signal from the filtering outputterminals 521 and 522 and then transforming the filtered signal into adriving signal, output at the driving output terminals 1521 and 1522 fordriving the LED module.

When the mode switching circuit 980 determines on performing a seconddriving mode, the mode switch 981 conducts current in the secondconductive path through the terminals 983 and 984 and the firstconductive path through the terminals 983 and 985 is in a cutoff state.In this case, the driving output terminal 1521 is coupled to thefiltering output terminal 521, and therefore the driving circuit 1730stops working, and a filtered signal is input through the filteringoutput terminals 521 and 522 to the driving output terminals 1521 and1522 for driving the LED module, while bypassing the inductor 1732 andthe freewheeling diode 1733 in the driving circuit 1730.

FIG. 32F is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32F, a mode switching circuit 1680 includes a mode switch 1681being suitable for use with the driving circuit 1830 in FIG. 29E.Referring to FIGS. 32F and 29E, the mode switch 1681 has three terminals1683, 1684, and 1685, wherein the terminal 1683 is coupled to thefiltering output terminal 521, the terminal 1684 is coupled to thedriving output terminal 1521, and the terminal 1685 is coupled to switch1835 in the driving circuit 1830.

When the mode switching circuit 1680 determines on performing a firstdriving mode, the mode switch 1681 conducts current in a firstconductive path through the terminals 1683 and 1685, and a secondconductive path through the terminals 1683 and 1684 is in a cutoffstate. In this case, the filtering output terminal 521 is coupled to theswitch 1835, and therefore the driving circuit 1830 is working normally,which working includes receiving a filtered signal from the filteringoutput terminals 521 and 522 and then transforming the filtered signalinto a driving signal, output at the driving output terminals 1521 and1522 for driving the LED module.

When the mode switching circuit 1680 determines on performing a seconddriving mode, the mode switch 1681 conducts current in the secondconductive path through the terminals 1683 and 1684 and the firstconductive path through the terminals 1683 and 1685 is in a cutoffstate. In this case, the driving output terminal 1521 is coupled to thefiltering output terminal 521, and therefore the driving circuit 1830stops working, and a filtered signal is input through the filteringoutput terminals 521 and 522 to the driving output terminals 1521 and1522 for driving the LED module, while bypassing the inductor 1832 andthe switch 1835 in the driving circuit 1830.

FIG. 32G is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32G, a mode switching circuit 1780 includes a mode switch 1781being suitable for use with the driving circuit 1830 in FIG. 29E.Referring to FIGS. 32G and 29E, the mode switch 1781 has three terminals1783, 1784, and 1785, wherein the terminal 1783 is coupled to thefiltering output terminal 521, the terminal 1784 is coupled to thedriving output terminal 1521, and the terminal 1785 is coupled toinductor 1832 in the driving circuit 1830.

When the mode switching circuit 1780 determines on performing a firstdriving mode, the mode switch 1781 conducts current in a firstconductive path through the terminals 1783 and 1785, and a secondconductive path through the terminals 1783 and 1784 is in a cutoffstate. In this case, the filtering output terminal 521 is coupled to theinductor 1832, and therefore the driving circuit 1830 is workingnormally, which working includes receiving a filtered signal from thefiltering output terminals 521 and 522 and then transforming thefiltered signal into a driving signal, output at the driving outputterminals 1521 and 1522 for driving the LED module.

When the mode switching circuit 1780 determines on performing a seconddriving mode, the mode switch 1781 conducts current in the secondconductive path through the terminals 1783 and 1784 and the firstconductive path through the terminals 1783 and 1785 is in a cutoffstate. In this case, the driving output terminal 1521 is coupled to thefiltering output terminal 521, and therefore the driving circuit 1830stops working, and a filtered signal is input through the filteringoutput terminals 521 and 522 to the driving output terminals 1521 and1522 for driving the LED module, while bypassing the inductor 1832 andthe switch 1835 in the driving circuit 1830.

FIG. 32H is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32H, a mode switching circuit 1880 includes two mode switches 1881and 1882 being suitable for use with the driving circuit 1930 in FIG.29F. Referring to FIGS. 32H and 29F, the mode switch 1881 has threeterminals 1883, 1884, and 1885, wherein the terminal 1883 is coupled tothe driving output terminal 1521, the terminal 1884 is coupled to thefiltering output terminal 521, and the terminal 1885 is coupled to thefreewheeling diode 1933 in the driving circuit 1930. And the mode switch1882 has three terminals 1886, 1887, and 1888, wherein the terminal 1886is coupled to the driving output terminal 1522, the terminal 1887 iscoupled to the filtering output terminal 522, and the terminal 1888 iscoupled to the filtering output terminal 521.

When the mode switching circuit 1880 determines on performing a firstdriving mode, the mode switch 1881 conducts current in a firstconductive path through the terminals 1883 and 1885, and a secondconductive path through the terminals 1883 and 1884 is in a cutoffstate, and the mode switch 1882 conducts current in a third conductivepath through the terminals 1886 and 1888, and a fourth conductive paththrough the terminals 1886 and 1887 is in a cutoff state. In this case,the driving output terminal 1521 is coupled to the freewheeling diode1933, and the filtering output terminal 521 is coupled to the drivingoutput terminal 1522. Therefore the driving circuit 1930 is workingnormally, which working includes receiving a filtered signal from thefiltering output terminals 521 and 522 and then transforming thefiltered signal into a driving signal, output at the driving outputterminals 1521 and 1522 for driving the LED module.

When the mode switching circuit 1880 determines on performing a seconddriving mode, the mode switch 1881 conducts current in the secondconductive path through the terminals 1883 and 1884, and the firstconductive path through the terminals 1883 and 1885 is in a cutoffstate, and the mode switch 1882 conducts current in the fourthconductive path through the terminals 1886 and 1887, and the thirdconductive path through the terminals 1886 and 1888 is in a cutoffstate. In this case, the driving output terminal 1521 is coupled to thefiltering output terminal 521, and the filtering output terminal 522 iscoupled to the driving output terminal 1522. Therefore the drivingcircuit 1930 stops working, and a filtered signal is input through thefiltering output terminals 521 and 522 to the driving output terminals1521 and 1522 for driving the LED module, while bypassing thefreewheeling diode 1933 and the switch 1935 in the driving circuit 1930.

FIG. 32I is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment of the present invention. Referring toFIG. 32I, a mode switching circuit 1980 includes two mode switches 1981and 1982 being suitable for use with the driving circuit 1930 in FIG.29F. Referring to FIGS. 32I and 29F, the mode switch 1981 has threeterminals 1983, 1984, and 1985, wherein the terminal 1983 is coupled tothe filtering output terminal 522, the terminal 1984 is coupled to thedriving output terminal 1522, and the terminal 1985 is coupled to switch1935 in the driving circuit 1930. And the mode switch 1982 has threeterminals 1986, 1987, and 1988, wherein the terminal 1986 is coupled tothe filtering output terminal 521, the terminal 1987 is coupled to thedriving output terminal 1521, and the terminal 1988 is coupled to thedriving output terminal 1522.

When the mode switching circuit 1980 determines on performing a firstdriving mode, the mode switch 1981 conducts current in a firstconductive path through the terminals 1983 and 1985, and a secondconductive path through the terminals 1983 and 1984 is in a cutoffstate, and the mode switch 1982 conducts current in a third conductivepath through the terminals 1986 and 1988, and a fourth conductive paththrough the terminals 1986 and 1987 is in a cutoff state. In this case,driving output terminal 1522 is coupled to the filtering output terminal521, and the filtering output terminal 522 is coupled to the switch1935. Therefore the driving circuit 1930 is working normally, whichworking includes receiving a filtered signal from the filtering outputterminals 521 and 522 and then transforming the filtered signal into adriving signal, output at the driving output terminals 1521 and 1522 fordriving the LED module.

When the mode switching circuit 1980 determines on performing a seconddriving mode, the mode switch 1981 conducts current in the secondconductive path through the terminals 1983 and 1984, and the firstconductive path through the terminals 1983 and 1985 is in a cutoffstate, and the mode switch 1982 conducts current in the fourthconductive path through the terminals 1986 and 1987, and the thirdconductive path through the terminals 1986 and 1988 is in a cutoffstate. In this case, the driving output terminal 1521 is coupled to thefiltering output terminal 521, and the filtering output terminal 522 iscoupled to the driving output terminal 1522. Therefore the drivingcircuit 1930 stops working, and a filtered signal is input through thefiltering output terminals 521 and 522 to the driving output terminals1521 and 1522 for driving the LED module, while bypassing thefreewheeling diode 1933 and the switch 1935 in the driving circuit 1930.

It's worth noting that the mode switches in the above embodiments mayeach comprise, for example, a single-pole double-throw switch, orcomprise two semiconductor switches (such as metal oxide semiconductortransistors), for switching a conductive path on to conduct currentwhile leaving the other conductive path cutoff. Each of the twoconductive paths provides a path for conducting the filtered signal,allowing the current of the filtered signal to flow through one of thetwo paths, thereby achieving the function of mode switching orselection. For example, with reference to FIG. 24A, when the lampdriving circuit 505 is not present and the LED tube lamp 500 is directlysupplied by the AC power supply 508, the mode switching circuit maydetermine on performing a first driving mode in which the drivingcircuit transforms the filtered signal into a driving signal with alogic level meeting a required logic level to properly drive the LEDmodule to emit light. On the other hand, when the lamp driving circuit505 is present, the mode switching circuit may determine on performing asecond driving mode in which the filtered signal is (almost) directlyused to drive the LED module to emit light; or alternatively the modeswitching circuit may determine on performing the first driving mode todrive the LED module to emit light.

FIG. 33A is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to FIG.24B, the embodiment of FIG. 33A includes two rectifying circuits 510 and540, a filtering circuit 520, and a driving circuit 1530, and furtherincludes a ballast-compatible circuit 1510. In this embodiment, adriving circuit 1530 and an LED module 630 compose the LED lightingmodule 530. The ballast-compatible circuit 1510 may be coupled betweenthe pin 501 and/or pin 502 and the rectifying circuit 510. Thisembodiment is explained assuming the ballast-compatible circuit 1510 tobe coupled between the pin 501 and the rectifying circuit 510.

In an initial stage upon the activation of the driving system of thelamp driving circuit 505, the lamp driving circuit 505's ability tooutput relevant signal(s) has not risen to a standard state. However, inthe initial stage the power supply module of the LED lamp instantly orrapidly receives or conducts the AC driving signal provided by the lampdriving circuit 505, which initial conduction is likely to fail thestarting of the LED lamp by the lamp driving circuit 505 as the lampdriving circuit 505 is initially loaded by the LED lamp in this stage.For example, the internal components of the lamp driving circuit 505 mayneed to retrieve power from a transformed output in the lamp drivingcircuit 505 in order to maintain their operation upon the activation. Inthis case, the activation of the lamp driving circuit 505 may end upfailing as its output voltage could not normally rise to a requiredlogic level in this initial stage; or the quality factor (Q) of aresonant circuit in the lamp driving circuit 505 may vary as a result ofthe initial loading from the LED lamp, so as to cause the failure of theactivation.

In this embodiment, in the initial stage upon activation, theballast-compatible circuit 1510 will be in an open-circuit state,preventing the energy of the AC driving signal from reaching the LEDmodule. After a defined delay upon the AC driving signal as an externaldriving signal being input to the LED tube lamp, the ballast-compatiblecircuit 1510 switches from a cutoff state during the delay to aconducting state, allowing the energy of the AC driving signal to startto reach the LED module. By means of the delayed conduction of theballast-compatible circuit 1510, operation of the LED lamp simulates thelamp-starting characteristics of a fluorescent lamp, that is, internalgases of the fluorescent lamp will normally discharge for light emissionafter a delay upon activation of a driving power supply. Therefore, theballast-compatible circuit 1510 further improves the compatibility ofthe LED lamp with the lamp driving circuits 505 such as an electronicballast.

FIG. 33B is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to FIG.33A, a ballast-compatible circuit 1510 in the embodiment of FIG. 33B iscoupled between the pin 503 and/or pin 504 and the rectifying circuit540. As explained regarding the ballast-compatible circuit 1510 in FIG.33A, the ballast-compatible circuit 1510 in FIG. 33B performs thefunction of delaying the starting of the LED lamp, or causing the inputof the AC driving signal to be delayed for a predefined time, in orderto prevent the failure of starting by the lamp driving circuits 505 suchas an electronic ballast.

Apart from coupling the ballast-compatible circuit 1510 between theterminal pin(s) and the rectifying circuit in the above embodiments, theballast-compatible circuit 1510 may alternatively be included within arectifying circuit with a different structure. FIG. 33C illustrates anarrangement with a ballast-compatible circuit in an LED lamp accordingto a preferred embodiment of the present invention. Referring to FIG.33C, the rectifying circuit assumes the circuit structure of therectifying circuit 810 in FIG. 25C. The rectifying circuit 810 includesa rectifying unit 815 and a terminal adapter circuit 541. The rectifyingunit 815 is coupled to the pins 501 and 502, the terminal adaptercircuit 541 is coupled to the output terminals 511 and 512, and theballast-compatible circuit 1510 in FIG. 33C is coupled between therectifying unit 815 and the terminal adapter circuit 541. In this case,in the initial stage upon activation of the ballast, an AC drivingsignal as an external driving signal is input to the LED tube lamp,where the AC driving signal can only reach the rectifying unit 815, butcannot reach other circuits such as the terminal adapter circuit 541,other internal filter circuitry, and the LED lighting module. Moreover,the parasitic capacitors associated with the rectifying diodes 811 and812 within the rectifying unit 815 are quite small in capacitance andthus can be ignored. Accordingly, the lamp driving circuit 505 in theinitial stage isn't loaded with or effectively connected to theequivalent capacitor or inductor of the power supply module of the LEDlamp, and the quality factor (Q) of the lamp driving circuit 505 istherefore not adversely affected in this stage, resulting in asuccessful starting of the LED lamp by the lamp driving circuit 505.

It's worth noting that under the condition that the terminal adaptercircuit 541 doesn't include components such as capacitors or inductors,interchanging the rectifying unit 815 and the terminal adapter circuit541 in position, meaning the rectifying unit 815 is connected to theoutput terminals 511 and 512 and the terminal adapter circuit 541 isconnected to the pins 501 and 502, doesn't affect or alter the functionof the ballast-compatible circuit 1510.

Further, as explained in FIGS. 25A-25D, when a rectifying circuit isconnected to the pins 503 and 504 instead of the pins 501 and 502, thisrectifying circuit may constitute the rectifying circuit 540. That is,the circuit arrangement with a ballast-compatible circuit 1510 in FIG.33C may be alternatively included in the rectifying circuit 540 insteadof the rectifying circuit 810, without affecting the function of theballast-compatible circuit 1510.

In some embodiments, as described above the terminal adapter circuit 541doesn't include components such as capacitors or inductors. Or when therectifying circuit 610 in FIG. 25A constitutes the rectifying circuit510 or 540, the parasitic capacitances in the rectifying circuit 510 or540 are quite small and thus can be ignored. These conditions contributeto not affecting the quality factor of the lamp driving circuit 505.

FIG. 33D is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to theembodiment of FIG. 33A, a ballast-compatible circuit 1510 in theembodiment of FIG. 33D is coupled between the rectifying circuit 540 andthe filtering circuit 520. Since the rectifying circuit 540 also doesn'tinclude components such as capacitors or inductors, the function of theballast-compatible circuit 1510 in the embodiment of FIG. 33D will notbe affected.

FIG. 33E is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to theembodiment of FIG. 33A, a ballast-compatible circuit 1510 in theembodiment of FIG. 33E is coupled between the rectifying circuit 510 andthe filtering circuit 520. Similarly, since the rectifying circuit 510doesn't include components such as capacitors or inductors, the functionof the ballast-compatible circuit 1510 in the embodiment of FIG. 33Ewill not be affected.

FIG. 33F is a schematic diagram of the ballast-compatible circuitaccording to an embodiment of the present invention. Referring to FIG.33F, a ballast-compatible circuit 1610 has an initial state in which anequivalent open-circuit is obtained at the ballast-compatible circuitinput and output terminals 1611 and 1621. Upon receiving an input signalat the ballast-compatible circuit input terminal 1611, a delay will passuntil a current conduction occurs through and between theballast-compatible circuit input and output terminals 1611 and 1621,transmitting the input signal to the ballast-compatible circuit outputterminal 1621.

The Ballast-compatible circuit 1610 includes a diode 1612, multipleresistors 1613, 1615, 1618, 1620, and 1622, a bidirectional triodethyristor (TRIAC) 1614, a DIAC or symmetrical trigger diode 1617, acapacitor 1619, and ballast-compatible circuit input and outputterminals 1611 and 1621. It's noted that the resistance of resistor 1613should be quite large so that when the bidirectional triode thyristor1614 is cutoff in an open-circuit state, an equivalent open-circuit isobtained at ballast-compatible circuit input and output terminals 1611and 1621.

The bidirectional triode thyristor 1614 is coupled between theballast-compatible circuit input and output terminals 1611 and 1621, andthe resistor 1613 is also coupled between the ballast-compatible circuitinput and output terminals 1611 and 1621 and in parallel to thebidirectional triode thyristor 1614. The diode 1612, the resistors 1620and 1622, and the capacitor 1619 are series-connected in sequencebetween the ballast-compatible circuit input and output terminals 1611and 1621, and are connected in parallel to the bidirectional triodethyristor 1614. The diode 1612 has an anode connected to thebidirectional triode thyristor 1614, and has a cathode connected to anend of the resistor 1620. The bidirectional triode thyristor 1614 has acontrol terminal connected to a terminal of the symmetrical triggerdiode 1617, which has another terminal connected to an end of theresistor 1618, which has another end connected to a node connecting thecapacitor 1619 and the resistor 1622. The resistor 1615 is connectedbetween the control terminal of the bidirectional triode thyristor 1614and a node connecting the resistor 1613 and the capacitor 1619. In someembodiments, the resistors 1615, 1618, and 1620 could be omitted, andhence they are depicted in dotted line. When the resistor 1618 isomitted, another terminal of the symmetrical trigger diode 1617mentioned above is directly connected to the node connecting thecapacitor 1619 and the resistor 1622. And the cathode of the diode 1612is connected to the resistor 1622 directly when the resistor 1620 isomitted.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input to theballast-compatible circuit input terminal 1611, the bidirectional triodethyristor 1614 will be in an open-circuit state, not allowing the ACdriving signal to pass through and the LED lamp is therefore also in anopen-circuit state. In this state, the AC driving signal is charging thecapacitor 1619 through the diode 1612 and the resistors 1620 and 1622,gradually increasing the voltage of the capacitor 1619. Upon continuallycharging for a period of time, the voltage of the capacitor 1619increases to be above the trigger voltage value of the symmetricaltrigger diode 1617 so that the symmetrical trigger diode 1617 is turnedon in a conducting state. Then the conducting symmetrical trigger diode1617 will in turn trigger the bidirectional triode thyristor 1614 on ina conducting state. In this situation, the conducting bidirectionaltriode thyristor 1614 electrically connects the ballast-compatiblecircuit input and output terminals 1611 and 1621, allowing the ACdriving signal to flow through the ballast-compatible circuit input andoutput terminals 1611 and 1621, thus starting the operation of the powersupply module of the LED lamp. In this case the energy stored by thecapacitor 1619 will maintain the conducting state of the bidirectionaltriode thyristor 1614, to prevent the AC variation of the AC drivingsignal from causing the bidirectional triode thyristor 1614 andtherefore the ballast-compatible circuit 1610 to be cutoff again, or toprevent or reduce the bidirectional triode thyristor 1614 alternating orswitching between its conducting and cutoff states.

When the ballast-compatible circuit 1610 for the present embodiment isapplied to the application circuits shown in FIGS. 33C-33D, the diode1612 could be omitted because the ballast-compatible circuit 1610receives the signal that has rectified by the rectifying unit/circuit.In some cases, the bidirectional triode thyristor 1614 could be replacedwith a silicon controlled rectifier (SCR), and the symmetrical triggerdiode 1617 could be replaced with a thyristor surge suppresser. Thiskind of replacement does not affect the protection for the circuit.Further, using a silicon controlled rectifier instead of a bidirectionaltriode thyristor has a lower voltage drop across itself in conductionthan that across the bidirectional triode thyristor in conduction.

In general, in hundreds of milliseconds upon activation of a lampdriving circuit 505 such as an electronic ballast, the output voltage ofthe ballast has risen above a certain voltage value as the outputvoltage hasn't been adversely affected by the sudden initial loadingfrom the LED lamp. In some cases, the AC voltage output from someinstant-start ballasts will be firstly kept at a fixed value for a shortperiod, such as 0.01 second, and in the meanwhile, the AC voltage at thefixed value is under 300V and rises or increases with time. However, anyloading added at the output of the instant-start ballast in this shortperiod would cause the instant-start ballast failing to pull up the ACvoltage for outputting, in particularly, this situation will be quiteoften when the input voltage of the instant-start ballast is 120V orbellow. Besides, a detection mechanism to detect whether lighting of afluorescent lamp is achieved may be disposed in lamp driving circuits505 such as an electronic ballast. In this detection mechanism, if afluorescent lamp fails to be lit up for a defined period of time, anabnormal state of the fluorescent lamp is detected, causing thefluorescent lamp to enter a protection state. In view of these facts, incertain embodiments, the delay provided by the ballast-compatiblecircuit 1610 until conduction of the ballast-compatible circuit 1610 andthen the LED lamp should be bigger than 0.01 second and may be in therange of about 0.1-3 seconds.

It's worth noting that an additional capacitor 1623 may be coupled inparallel to the resistor 1622. The capacitor 1623 works to reflect orsupport instantaneous change in the voltage between theballast-compatible circuit input and output terminals 1611 and 1621, andwill not affect the function of delayed conduction performed by theballast-compatible circuit 1610.

FIG. 33G is a block diagram of a power supply module in an LED lampaccording to an embodiment of the present invention. Compared to theembodiment of FIG. 24A, the lamp driving circuit 505 in the embodimentof FIG. 33G drives a plurality of LED tube lamps 500 connected inseries, wherein a ballast-compatible circuit 1610 is disposed in each ofthe LED tube lamps 500. For the convenience of illustration, twoseries-connected LED tube lamps 500 are assumed for example andexplained as follows.

Because the two ballast-compatible circuits 1610 respectively of the twoLED tube lamps 500 can actually have different delays until conductionof the LED tube lamps 500, due to various factors such as errorsoccurring in production processes of some components, the actual timingof conduction of each of the ballast-compatible circuits 1610 isdifferent. Upon activation of a lamp driving circuit 505, the voltage ofthe AC driving signal provided by the lamp driving circuit 505 will beshared out by the two LED tube lamps 500 roughly equally. Subsequentlywhen only one of the two LED tube lamps 500 first enters a conductingstate, the voltage of the AC driving signal then will be borne mostly orentirely by the other LED tube lamp 500. This situation will cause thevoltage across the ballast-compatible circuits 1610 in the other LEDtube lamp 500 that's not conducting to suddenly increase or be doubled,meaning the voltage between the ballast-compatible circuit input andoutput terminals 1611 and 1621 might even be suddenly doubled. In viewof this, if the capacitor 1623 is included, the voltage division effectbetween the capacitors 1619 and 1623 will instantaneously increase thevoltage of the capacitor 1619, making the symmetrical trigger diode 1617triggering the bidirectional triode thyristor 1614 into a conductingstate, thus causing the two ballast-compatible circuits 1610respectively of the two LED tube lamps 500 to become conducting almostat the same time. Therefore, by introducing the capacitor 1623, thesituation, where one of the two ballast-compatible circuits 1610respectively of the two series-connected LED tube lamps 500 that isfirst conducting has its bidirectional triode thyristor 1614 thensuddenly cutoff as having insufficient current passing through due tothe discrepancy between the delays provided by the twoballast-compatible circuits 1610 until their respective conductions, canbe avoided. Therefore, using each ballast-compatible circuit 1610 withthe capacitor 1623 further improves the compatibility of theseries-connected LED tube lamps with each of the lamp driving circuits505 such as an electronic ballast.

In practical use, a suggested range for the capacitance of the capacitor1623 is about 10 pF to about 1 nF, which may in some cases be in therange of about 10 pF to about 100 pF, and may be about 47 pF in certainembodiments.

It's worth noting that the diode 1612 is used or configured to rectifythe signal for charging the capacitor 1619. Therefore, with reference toFIGS. 33C, 33D, and 33E, in the case when the ballast-compatible circuit1610 is arranged following a rectifying unit or circuit, the diode 1612may be omitted. Thus the diode 1612 is depicted in a dotted line in FIG.33F.

FIG. 33H is a schematic diagram of the ballast-compatible circuitaccording to another embodiment of the present invention. Referring toFIG. 33H, a ballast-compatible circuit 1710 has an initial state inwhich an equivalent open-circuit is obtained at the ballast-compatiblecircuit input and output terminals 1711 and 1721. Upon receiving aninput signal at the ballast-compatible circuit input terminal 1711, theballast-compatible circuit 1710 will be in a cutoff state when the logiclevel of the input external driving signal is below a defined valuecorresponding to a conduction delay of the ballast-compatible circuit1710; and the ballast-compatible circuit 1710 will enter a conductingstate upon the logic level of the input external driving signal reachingthe defined value, thus transmitting the input signal to theballast-compatible circuit output terminal 1721. In some cases, thedefined value is equal to or bigger than 400V.

The ballast-compatible circuit 1710 includes a bidirectional triodethyristor (TRIAC) 1712, a DIAC or symmetrical trigger diode 1713,multiple resistors 1714, 1716, and 1717, and a capacitor 1715. Thebidirectional triode thyristor 1712 has a first terminal connected tothe ballast-compatible circuit input terminal 1711; a control terminalconnected to a terminal of the symmetrical trigger diode 1713 and an endof the resistor 1714; and a second terminal connected to another end ofthe resistor 1714. The capacitor 1715 has an end connected to anotherterminal of the symmetrical trigger diode 1713, and has another endconnected to the second terminal of the bidirectional triode thyristor1712. The resistor 1717 is in parallel connection with the capacitor1715, and is therefore also connected to another terminal of thesymmetrical trigger diode 1713 and the second terminal of thebidirectional triode thyristor 1712 mentioned above. And the resistor1716 has an end connected to the node connecting the capacitor 1715 andthe symmetrical trigger diode 1713, and has another end connected to theballast-compatible circuit output terminal 1721.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input to theballast-compatible circuit input terminal 1711, the bidirectional triodethyristor 1712 will be in an open-circuit state, not allowing the ACdriving signal to pass through and the LED lamp is therefore also in anopen-circuit state. The input of the AC driving signal causes apotential difference between the ballast-compatible circuit inputterminal 1711 and the ballast-compatible circuit output terminal 1721.When the AC driving signal increases with time to eventually reach asufficient amplitude (which is a defined logic level after the delay)after a period of time, the signal logic level at the ballast-compatiblecircuit output terminal 1721 has a reflected voltage at the controlterminal of the bidirectional triode thyristor 1712 after passingthrough the resistor 1716, the parallel-connected capacitor 1715 and theresistor 1717, and the resistor 1714, wherein the reflected voltage thentriggers the bidirectional triode thyristor 1712 into a conductingstate. This conducting state makes the ballast-compatible circuit 1710entering a conducting state which causes the LED lamp to operatenormally. Upon the bidirectional triode thyristor 1712 conducting, acurrent flows through the resistor 1716 and then charges the capacitor1715 to store a specific voltage on the capacitor 1715. In this case,the energy stored by the capacitor 1715 will maintain the conductingstate of the bidirectional triode thyristor 1712, to prevent the ACvariation of the AC driving signal from causing the bidirectional triodethyristor 1712 (or the ballast-compatible circuit 1710) to be cutoffagain, or to prevent the situation of the bidirectional triode thyristor1712 alternating or switching between its conducting and cutoff states.

FIG. 33I illustrates the ballast-compatible circuit according to anembodiment of the present invention. Referring to FIG. 33I, aballast-compatible circuit 1810 includes a housing 1812, a metallicelectrode 1813, a bimetallic strip 1814, and a heating filament 1816.The metallic electrode 1813 and the heating filament 1816 protrude fromthe housing 1812, so that they each have a portion inside the housing1812 and a portion outside of the housing 1812. The metallic electrode1813's outside portion has a ballast-compatible circuit input terminal1811, and the heating filament 1816's outside portion has aballast-compatible circuit output terminal 1821. The housing 1812 ishermetic or tightly sealed and contains inertial gas 1815 such as heliumgas. The bimetallic strip 1814 is inside the housing 1812 and isphysically and electrically connected to the portion of heating filament1816 that is inside the housing 1812. And there is a spacing between thebimetallic strip 1814 and the metallic electrode 1813, so that theballast-compatible circuit input terminal 1811 and theballast-compatible circuit output terminal 1821 are not electricallyconnected in the initial state of the ballast-compatible circuit 1810.The bimetallic strip 1814 may include two metallic strips with differenttemperature coefficients, wherein the metallic strip closer to themetallic electrode 1813 has a smaller temperature coefficient, and themetallic strip more away from the metallic electrode 1813 has a largertemperature coefficient.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input at theballast-compatible circuit input terminal 1811 and theballast-compatible circuit output terminal 1821, a potential differencebetween the metallic electrode 1813 and the heating filament 1816 isformed. When the potential difference increases enough to cause electricarc or arc discharge through the inertial gas 1815, meaning when the ACdriving signal increases with time to eventually reach the defined logiclevel after a delay, then the inertial gas 1815 is then heated to causethe bimetallic strip 1814 to swell toward the metallic electrode 1813(as in the direction of the broken-line arrow in FIG. 33I), with thisswelling eventually causing the bimetallic strip 1814 to bear against orclose to the metallic electrode 1813, forming the physical andelectrical connections between them. In this situation, there iselectrical conduction between the ballast-compatible circuit inputterminal 1811 and the ballast-compatible circuit output terminal 1821.Then the AC driving signal flows through and thus heats the heatingfilament 1816. In this heating process, the heating filament 1816 allowsa current to flow through when electrical conduction exists between themetallic electrode 1813 and the bimetallic strip 1814, causing thetemperature of the bimetallic strip 1814 to be above a definedconduction temperature. As a result, since the respective temperature ofthe two metallic strips of the bimetallic strip 1814 with differenttemperature coefficients are maintained above the defined conductiontemperature, the bimetallic strip 1814 will bend against or toward themetallic electrode 1813, thus maintaining or supporting the physicaljoining or connection between the bimetallic strip 1814 and the metallicelectrode 1813. Therefore, upon receiving an input signal at theballast-compatible circuit input and output terminals 1811 and 1821, adelay will pass until an electrical/current conduction occurs throughand between the ballast-compatible circuit input and output terminals1811 and 1821.

Therefore, an exemplary ballast-compatible circuit such as describedherein may be coupled between any pin and any rectifying circuitdescribed above in the invention, wherein the ballast-compatible circuitwill be in a cutoff state in a defined delay upon an external drivingsignal being input to the LED tube lamp, and will enter a conductingstate after the delay. Otherwise, the ballast-compatible circuit will bein a cutoff state when the logic level of the input external drivingsignal is below a defined value corresponding to a conduction delay ofthe ballast-compatible circuit; and the ballast-compatible circuit willenter a conducting state upon the logic level of the input externaldriving signal reaching the defined value. Accordingly, thecompatibility of the LED tube lamp described herein with the lampdriving circuits 505 such as an electronic ballast is further improvedby using such a ballast-compatible circuit.

FIG. 34A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 24B, the present embodiment comprises two rectifyingcircuits 510 and 540, a filtering circuit 520, and a driving circuit1530, and further comprises two ballast-compatible circuits 1540. Inthis embodiment, a driving circuit 1530 and an LED module 630 composethe LED lighting module 530. The two ballast-compatible circuits 1540are coupled respectively between the pin 503 and the rectifying outputterminal 511 and between the pin 504 and the rectifying output terminal511. Referring to FIG. 24A, the lamp driving circuit 505 is anelectronic ballast for supplying an AC driving signal to drive the LEDlamp of the present invention.

Two ballast-compatible circuits 1540 are initially in conducting states,and then enter into cutoff states in a delay. Therefore, in an initialstage upon activation of the lamp driving circuit 505, the AC drivingsignal is transmitted through the pin 503, the correspondingballast-compatible circuit 1540, the rectifying output terminal 511 andthe rectifying circuit 510, or through the pin 504, the correspondingballast-compatible circuit 1540, the rectifying output terminal 511 andthe rectifying circuit 510 of the LED lamp, and the filtering circuit520 and the LED lighting module 530 of the LED lamp are bypassed.Thereby, the LED lamp presents almost no load and does not affect thequality factor of the lamp driving circuit 505 at the beginning, and sothe lamp driving circuit can be activated successfully. The twoballast-compatible circuits 1540 are cut off after a time period whilethe lamp driving circuit 505 has been activated successfully. Afterthat, the lamp driving circuit 505 has a sufficient drive capability fordriving the LED lamp to emit light.

FIG. 34B is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 34A, two ballast-compatible circuits 1540 are changed tobe coupled respectively between the pin 503 and the rectifying outputterminal 512 and between the pin 504 and the rectifying output terminal512. Similarly, two ballast-compatible circuits 1540 are initially inconducting states, and then changed to cutoff states after an objectivedelay. Thereby, the lamp driving circuit 505 drives the LED lamp to emitlight after the lamp driving circuit 505 has activated.

It is worth noting that the arrangement of the two ballast-compatiblecircuits 1540 may be changed to be coupled between the pin 501 and therectifying terminal 511 and between the pin 502 and the rectifyingterminal 511, or between the pin 501 and the rectifying terminal 512 andbetween the pin 502 and the rectifying terminal 512, for having the lampdriving circuit 505 drive the LED lamp to emit light after beingactivated.

FIG. 34C is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIGS. 34A and 34B, the rectifying circuit 810 shown in FIG. 25Creplaces the rectifying circuit 540, and the rectifying unit 815 of therectifying circuit 810 is coupled to the pins 503 and 504 and theterminal adapter circuit 541 thereof is coupled to the rectifying outputterminals 511 and 512. The arrangement of the two ballast-compatiblecircuits 1540 is also changed to be coupled respectively between the pin501 and the half-wave node 819 and between the pin 502 and the half-wavenode 819.

In an initial stage upon activation of the lamp driving circuit 505, twoballast-compatible circuits 1540 are initially in conducting states. Atthis moment, the AC driving signal is transmitted through the pin 501,the corresponding ballast-compatible circuit 1540, the half-wave node819 and the rectifying unit 815, or the pin 502, the correspondingballast-compatible circuit 1540, the half-wave node 819 and therectifying unit 815 of the LED lamp, and the terminal adapter circuit541, the filtering circuit 520 and the LED lighting module 530 of theLED lamp are bypassed. Thereby, the LED lamp presents almost no load anddoes not affect the quality factor of the lamp driving circuit 505 atthe beginning, and so the lamp driving circuit can be activatedsuccessfully. The two ballast-compatible circuits 1540 are cut off aftera time period while the lamp driving circuit 505 has been activatedsuccessfully. After that, the lamp driving circuit 505 has a sufficientdrive capability for driving the LED lamp to emit light.

It is worth noting that the rectifying circuit 810 shown in FIG. 25C mayreplace the rectifying circuit 510 of the present embodiment shown inFIG. 34C. Wherein, the rectifying unit 815 of the rectifying circuit 810is coupled to the pins 501 and 502 and the terminal adapter circuit 541thereof is coupled to the rectifying output terminals 511 and 512. Thearrangement of the two ballast-compatible circuits 1540 is also changedto be coupled respectively between the pin 503 and the half-wave node819 and between the pin 504 and the half-wave node 819. Accordingly, theballast-compatible circuit 1540 can still make the lamp driving circuit505 drive the LED lamp to emit light after being activated.

FIG. 34D is a schematic diagram of a ballast-compatible circuitaccording to an embodiment of the present invention, which is applicableto the embodiments shown in FIGS. 34A and 34C and the describedmodification thereof.

A ballast-compatible circuit 1640 comprises multiple resistors 1643,1645, 1648 and 1650, two capacitors 1644 and 1649, two diodes 1647 and1652, two bipolar junction transistors (BJT) 1646 and 1651, aballast-compatible circuit terminal 1641 and a ballast-compatiblecircuit terminal 1642. One end of the resistor 1645 is coupled to theballast-compatible circuit terminal 1641, and the other end is coupledto an emitter of the BJT 1646. A collector of the BJT 1646 is coupled toa positive end of the diode 1647, and a negative end thereof is coupledto the ballast-compatible circuit terminal 1642. The resistor 1643 andthe capacitor 1644 are connected in series with each other and coupledbetween the emitter and the collector of the BJT 1646, and theconnection node of the resistor 1643 and the capacitor 1644 is coupledto a base of the BJT 1646. One end of the resistor 1650 is coupled tothe ballast-compatible circuit terminal 1642, and the other end iscoupled to an emitter of the BJT 1651. A collector of the BJT 1651 iscoupled to a positive end of the diode 1652, and a negative end thereofis coupled to the ballast-compatible circuit terminal 1641. The resistor1648 and the capacitor 1649 are connected in series with each other andcoupled between the emitter and the collector of the BJT 1651, and theconnection node of the resistor 1648 and the capacitor 1649 is coupledto a base of the BJT 1651.

In an initial stage upon the lamp driving circuit 505, e.g. electronicballast, being activated, voltages across the capacitors 1644 and 1649are about zero. At this time, the BJTs 1646 and 1651 are in conductingstate and the bases thereof allow currents to flow through. Therefore,in an initial stage upon activation of the lamp driving circuit 505, theballast-compatible circuits 1640 are in conducting state. The AC drivingsignal charges the capacitor 1644 through the resistor 1643 and thediode 1647, and charges the capacitor 1649 through the resistor 1648 andthe diode 1652. After a time period, the voltages across the capacitors1644 and 1649 reach certain voltages so as to reduce the voltages of theresistors 1643 and 1648, thereby cutting off the BJTs 1646 and 1651,i.e., the states of the BJTs 1646 and 1651 are cutoff states. At thistime, the state of the ballast-compatible circuit 1640 is changed to thecutoff state. Thereby, the internal capacitor(s) and inductor(s) do notaffect in Q-factor of the lamp driving circuit 505 at the beginning forensuring the lamp driving circuit activating. Hence, theballast-compatible circuit 1640 improves the compatibility of LED lampwith the electronic ballast.

In summary, the two ballast-compatible circuits of the present inventionare respectively coupled between a connection node of the rectifyingcircuit and the filtering circuit (i.e., the rectifying output terminal511 or 512) and the pin 501 and between the connection node and the pin502, or coupled between the connection node and the pin 503 and theconnection node and the pin 504. The two ballast-compatible circuitsconduct for an objective delay upon the external driving signal beinginput into the LED tube lamp, and then are cut off after the objectivedelay for enhancing the compatibility of the LED lamp with theelectronic ballast.

FIG. 35A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 24B, the LED tube lamp comprises two rectifying circuits510 and 540, a filtering circuit 520, and an LED lighting module 530,and further comprises two filament-simulating circuits 1560. Thefilament-simulating circuits 1560 are respectively coupled between thepins 501 and 502 and coupled between the pins 503 and 504, for improvinga compatibility with a lamp driving circuit having filament detectionfunction, e.g.: program-start ballast.

In an initial stage upon the lamp driving circuit having filamentdetection function being activated, the lamp driving circuit willdetermine whether the filaments of the lamp operate normally or are inan abnormal condition of short-circuit or open-circuit. Once determiningthe abnormal condition of the filaments, the lamp driving circuit stopsoperating and enters a protection state. In order to avoid a situationwhere the lamp driving circuit erroneously determines the LED tube lampto be abnormal due to the LED tube lamp having no filament, the twofilament-simulating circuits 1560 simulate the operation of actualfilaments of a fluorescent tube to have the lamp driving circuit enterinto a normal state to start the LED lamp normally.

FIG. 35B is a schematic diagram of a filament-simulating circuitaccording to an embodiment of the present invention. Thefilament-simulating circuit comprises a capacitor 1663 and a resistor1665 connected in parallel, and two ends of the capacitor 1663 and twoends of the resistor 1665 are re respectively coupled to the filamentsimulating terminals 1661 and 1662. Referring to FIG. 35A, the filamentsimulating terminals 1661 and 1662 of the two filament simulatingcircuits 1660 are respectively coupled to the pins 501 and 502 and thepins 503 and 504. During the filament detection process, the lampdriving circuit outputs a detection signal to detect the state of thefilaments. The detection signal passes the capacitor 1663 and theresistor 1665 and so the lamp driving circuit determines that thefilaments of the LED lamp are normal.

In addition, a capacitance value of the capacitor 1663 is low and so acapacitive reactance (equivalent impedance) of the capacitor 1663 is farlower than an impedance of the resistor 1665 due to the lamp drivingcircuit outputting a high-frequency alternative current (AC) signal todrive LED lamp. Therefore, the filament-simulating circuit 1660 consumesfairly low power when the LED lamp operates normally, and so it almostdoes not affect the luminous efficiency of the LED lamp.

FIG. 35C is a schematic block diagram including a filament-simulatingcircuit according to an embodiment of the present invention. In thepresent embodiment, the filament-simulating circuit 1660 replaces theterminal adapter circuit 541 of the rectifying circuit 810 shown in FIG.25C, which is adopted as the rectifying circuit(s) 510 or/and 540 in theLED lamp. For example, the filament-simulating circuit 1660 of thepresent embodiment has both of filament simulating and terminal adaptingfunctions. Referring to FIG. 35A, the filament simulating terminals 1661and 1662 of the filament-simulating circuit 1660 are respectivelycoupled to the pins 501 and 502 or/and pins 503 and 504. The half-wavenode 819 of the rectifying unit 815 in the rectifying circuit 810 iscoupled to the filament simulating terminal 1662.

FIG. 35D is a schematic block diagram including a filament-simulatingcircuit according to another embodiment of the present invention.Compared to that shown in FIG. 35C, the half-wave node is changed to becoupled to the filament simulating terminal 1661, and thefilament-simulating circuit 1660 in the present embodiment still hasboth of filament simulating and terminal adapting functions.

FIG. 35E is a schematic diagram of a filament-simulating circuitaccording to another embodiment of the present invention. Afilament-simulating circuit 1760 comprises two capacitors 1763 and 1764,and two resistors 1765 and 1766. The capacitors 1763 and 1764 areconnected in series and coupled between the filament simulatingterminals 1661 and 1662. The resistors 1765 and 1766 are connected inseries and coupled between the filament simulating terminals 1661 and1662. Furthermore, the connection node of the capacitors 1763 and 1764is coupled to that of the resistors 1765 and 1766. Referring to FIG.35A, the filament simulating terminals 1661 and 1662 of thefilament-simulating circuit 1760 are respectively coupled to the pins501 and 502 and the pins 503 and 504. When the lamp driving circuitoutputs the detection signal for detecting the state of the filament,the detection signal passes the capacitors 1763 and 1764 and theresistors 1765 and 1766 so that the lamp driving circuit determines thatthe filaments of the LED lamp are normal.

It is worth noting that in some embodiments, capacitance values of thecapacitors 1763 and 1764 are low and so a capacitive reactance of theserially connected capacitors 1763 and 1764 is far lower than animpedance of the serially connected resistors 1765 and 1766 due to thelamp driving circuit outputting the high-frequency AC signal to driveLED lamp. Therefore, the filament-simulating circuit 1760 consumesfairly low power when the LED lamp operates normally, and so it almostdoes not affect the luminous efficiency of the LED lamp. Moreover, anyone of the capacitor 1763 and the resistor 1765 is short circuited or isan open circuit, or any one of the capacitor 1764 and the resistor 1766is short circuited or is an open circuit, the detection signal stillpasses through the filament-simulating circuit 1760 between the filamentsimulating terminals 1661 and 1662. Therefore, the filament-simulatingcircuit 1760 still operates normally when any one of the capacitor 1763and the resistor 1765 is short circuited or is an open circuit or anyone of the capacitor 1764 and the resistor 1766 is short circuited or isan open circuit, and so it has quite high fault tolerance.

The embodiment of filament-simulating circuit mentioned above could useceramic capacitor or metallized polypropylene film capacitor, such asthe ceramic capacitor in class 2, the metallized polypropylene filmcapacitor (X2). When the metallized polypropylene film capacitor (X2) isadopted, since its capacitance is smaller than 100 nF and it has a smallinherent impedance, it can make the current of the filament-simulatingcircuit down to tens mA to reduce power consumption. Also, the heatingcaused by the inherent impedance is smaller, the temperature could beabove 70 degrees Celsius or even in the range of 50-60 degrees Celsius.

In some cases, the circuit design adopts the flexible sheet to make allof or some of the LED components and the active/passive parts of the ACpower module being able to be disposed on the same flexible sheet ordifferent flexible sheets to simplify the structure design in the LEDlamp. The capacitor(s) may be preferable to, for example, X7Rmulti-layer ceramic capacitor and the capacitance thereof can in someembodiments be bigger than 100 nF.

FIG. 35F is a schematic block diagram including a filament-simulatingcircuit according to an embodiment of the present invention. In thepresent embodiment, the filament-simulating circuit 1860 replaces theterminal adapter circuit 541 of the rectifying circuit 810 shown in FIG.25C, which is adopted as the rectifying circuit 510 or/and 540 in theLED lamp. For example, the filament-simulating circuit 1860 of thepresent embodiment has both of filament simulating and terminal adaptingfunctions. An impedance of the filament-simulating circuit 1860 has anegative temperature coefficient (NTC), i.e., the impedance at a highertemperature is lower than that at a lower temperature. In the presentembodiment, the filament-simulating circuit 1860 comprises two NTCresistors 1863 and 1864 connected in series and coupled to the filamentsimulating terminals 1661 and 1662. Referring to FIG. 35A, the filamentsimulating terminals 1661 and 1662 are respectively coupled to the pins501 and 502 or/and the pins 503 and 504. The half-wave node 819 of therectifying unit 815 in the rectifying circuit 810 is coupled to aconnection node of the NTC resistors 1863 and 1864.

When the lamp driving circuit outputs the detection signal for detectingthe state of the filament, the detection signal passes the NTC resistors1863 and 1864 so that the lamp driving circuit determines that thefilaments of the LED lamp are normal. The impedance of the seriallyconnected NTC resistors 1863 and 1864 is gradually decreased with thegradually increasing of temperature due to the detection signal or apreheat process. When the lamp driving circuit enters into the normalstate to start the LED lamp normally, the impedance of the seriallyconnected NTC resistors 1863 and 1864 is decreased to a relative lowvalue and so the power consumption of the filament simulation circuit1860 is lower.

An exemplary impedance of the filament-simulating circuit 1860 can be 10ohms or more at room temperature (25 degrees Celsius) and may bedecreased to a range of about 2-10 ohms when the lamp driving circuitenters into the normal state. It may be preferred that the impedance ofthe filament-simulating circuit 1860 is decreased to a range of about3-6 ohms when the lamp driving circuit enters into the normal state.

FIG. 36A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 24B, the present embodiment comprises two rectifyingcircuits 510 and 540, a filtering circuit 520, and an LED lightingmodule 530, and further comprises an over voltage protection (OVP)circuit 1570. The OVP circuit 1570 is coupled to the filtering outputterminals 521 and 522 for detecting the filtered signal. The OVP circuit1570 clamps the logic level of the filtered signal when determining thelogic level thereof higher than a defined OVP value. Hence, the OVPcircuit 1570 protects the LED lighting module 530 from damage due to anOVP condition.

FIG. 36B is a schematic diagram of an overvoltage protection (OVP)circuit according to an embodiment of the present invention. An OVPcircuit 1670 comprises a voltage clamping diode 1671, such as zenerdiode, coupled to the filtering output terminals 521 and 522. Thevoltage clamping diode 1671 is conducted to clamp a voltage differenceat a breakdown voltage when the voltage difference of the filteringoutput terminals 521 and 522 (i.e., the logic level of the filteredsignal) reaches the breakdown voltage. The breakdown voltage may bepreferred in a range of about 40 V to about 100 V, and more preferred ina range of about 55 V to about 75V.

FIG. 37A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 35A, the present embodiment comprises two rectifyingcircuits 510 and 540, a filtering circuit 520, an LED lighting module530 and two filament-simulating circuits 1560, and further comprises aballast detection circuit 1590. The ballast detection circuit 1590 maybe coupled to any one of the pins 501, 502, 503 and 504 and acorresponding rectifying circuit of the rectifying circuits 510 and 540.In the present embodiment, the ballast detection circuit 1590 is coupledbetween the pin 501 and the rectifying circuit 510.

The ballast detection circuit 1590 detects the AC driving signal or asignal input through the pins 501, 502, 503 and 504, and determineswhether the input signal is provided by an electric ballast based on thedetected result.

FIG. 37B is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 37A, the rectifying circuit 810 shown in FIG. 25C replacesthe rectifying circuit 540 in the present embodiment. The ballastdetection circuit 1590 is coupled between the rectifying unit 815 andthe terminal adapter circuit 541. One of the rectifying unit 815 and theterminal adapter circuit 541 is coupled to the pins 503 and 504, and theother one is coupled to the rectifying output terminals 511 and 512. Inthe present embodiment, the rectifying unit 815 is coupled to the pins503 and 504, and the terminal adapter circuit 541 is coupled to therectifying output terminals 511 and 512. Similarly, the ballastdetection circuit 1590 detects the signal input through the pins 503 and504 for determining the input signal whether provided by an electricballast according to the frequency of the input signal.

In addition, the rectifying circuit 810 may replace the rectifyingcircuit 510 instead of the rectifying circuit 540, and the ballastdetection circuit 1590 is coupled between the rectifying unit 815 andthe terminal adapter circuit 541 in the rectifying circuit 510.

FIG. 37C is a block diagram of a ballast detection circuit according toan embodiment of the present invention. A ballast detection circuit 1590comprises a detection circuit 1590 a and a switch circuit 1590 b. Theswitch circuit 1590 b is coupled to two switch terminals 1591 and 1592.The detection circuit 1590 a is coupled to two detection terminals 1593and 1594 for detecting a signal transmitted through the detectionterminals 1593 and 1594. Alternatively, the switch terminals 1591 and1592 serves as the detection terminals and the detection terminals 1593and 1594 are omitted. For example, in certain embodiments, the switchcircuit 1590 b and the detection circuit 1590 a are commonly coupled tothe switch terminals 1591 and 1592, and the detection circuit 1590 adetects a signal transmitted through the switch terminals 1591 and 1592.Hence, the detection terminals 1593 and 1594 are depicted by dottedlines.

FIG. 37D is a schematic diagram of a ballast detection circuit accordingto an embodiment of the present invention. A ballast detection circuit1690 comprises a detection circuit 1690 a and a switch circuit 1690 b,and is coupled between the switch terminals 1591 and 1592. The detectioncircuit 1690 a comprises a symmetrical trigger diode 1691, two resistors1692 and 1696 and multiple capacitors 1693, 1697 and 1698. The switchcircuit 1690 b comprises a TRIAC 1699 and an inductor 1694.

The capacitor 1698 is coupled between the switch terminals 1591 and 1592for generating a detection voltage in response to a signal transmittedthrough the switch terminals 1591 and 1592. When the signal is a highfrequency signal, the capacitive reactance of the capacitor 1698 isfairly low and so the detection voltage generated thereby is quitesmall. Whereas the signal is a low frequency signal or a DC signal, thecapacitive reactance of the capacitor 1698 is quite high and so thedetection voltage generated thereby is quite high. The resistor 1692 andthe capacitor 1693 are connected in series and coupled between two endsof the capacitor 1698. The serially connected resistor 1692 and thecapacitor 1693 is used to filter the detection signal generated by thecapacitor 1698 and generates a filtered detection signal at a connectionnode thereof. The filter function of the resistor 1692 and the capacitor1693 is used to filter high frequency noise in the detection signal forpreventing the switch circuit 1690 b from misoperation due to the highfrequency noise. The resistor 1696 and the capacitor 1697 are connectedin series and coupled between two ends of the capacitor 1693, andtransmit the filtered detection signal to one end of the symmetricaltrigger diode 1691. The serially connected resistor 1696 and capacitor1697 performs second filtering of the filtered detection signal toenhance the filter effect of the detection circuit 1690 a. Based onrequirement for filtering logic levels of different applications, thecapacitor 1697 may be omitted and the end of the symmetrical triggerdiode 1691 is coupled to the connection node of the resistor 1692 andthe capacitor 1693 through the resistor 1696. Alternatively, both of theresistor 1696 and the capacitor 1697 are omitted and the end of thesymmetrical trigger diode 1691 is directly coupled to the connectionnode of the resistor 1692 and the capacitor 1693. Therefore, theresistor 1696 and the capacitor 1697 are depicted by dotted lines. Theother end of the symmetrical trigger diode 1691 is coupled to a controlend of the TRIAC 1699 of the switch circuit 1690 b. The symmetricaltrigger diode 1691 determines whether to generate a control signal 1695to trigger the TRIAC 1699 on according to a logic level of a receivedsignal. A first end of the TRIAC 1699 is coupled to the switch terminal1591 and a second end thereof is coupled to the switch terminal 1592through the inductor 1694. The inductor 1694 is used to protect theTRIAC 1699 from damage due to a situation where the signal transmittedinto the switch terminals 1591 and 1592 is over a maximum rate of riseof commutation voltage or switching voltage, a repetitive peak voltagein off-state or a maximum rate of change of current.

When the switch terminals 1591 and 1592 receive a low frequency signalor a DC signal, the detection signal generated by the capacitor 1698 ishigh enough to make the symmetrical trigger diode 1691 generate thecontrol signal 1695 to trigger the TRIAC 1699 on. At this time, theswitch terminals 1591 and 1592 are shorted to bypass the circuit(s)connected in parallel with the switch circuit 1690 b, such as a circuitcoupled between the switch terminals 1591 and 1592, the detectioncircuit 1690 a and the capacitor 1698.

In some embodiments, when the switch terminals 1591 and 1592 receive ahigh frequency AC signal, the detection signal generated by thecapacitor 1698 is not high enough to make the symmetrical trigger diode1691 generate the control signal 1695 to trigger the TRIAC 1699 on. Atthis time, the TRIAC 1699 is cut off and so the high frequency AC signalis mainly transmitted through an external circuit or the detectioncircuit 1690 a.

Hence, the ballast detection circuit 1690 can determine whether theinput signal is a high frequency AC signal provided by an electricballast. If yes, the high frequency AC signal is transmitted through theexternal circuit or the detection circuit 1690 a; if no, the inputsignal is transmitted through the switch circuit 1690 b, bypassing theexternal circuit and the detection circuit 1690 a.

It is worth noting that the capacitor 1698 may be replaced by externalcapacitor(s), such as at least one capacitor in the terminal adaptercircuits shown in FIG. 26A-C. Therefore, the capacitor 1698 may beomitted and be therefore depicted by a dotted line.

FIG. 37E is a schematic diagram of a ballast detection circuit accordingto an embodiment of the present invention. A ballast detection circuit1790 comprises a detection circuit 1790 a and a switch circuit 1790 b.The switch circuit 1790 b is coupled between the switch terminals 1591and 1592. The detection circuit 1790 a is coupled between the detectionterminals 1593 and 1594. The detection circuit 1790 a comprises twoinductors 1791 and 1792 with mutual induction, two capacitors 1793 and1796, a resistor 1794 and a diode 1797. The switch circuit 1790 bcomprises a switch 1799. In the present embodiment, the switch 1799 is ap-type depletion mode MOSFET, which is cut off when the gate voltage ishigher than a threshold voltage and is conducted when the gate voltageis lower than the threshold voltage.

The inductor 1792 is coupled between the detection terminals 1593 and1594 and induces a detection voltage in the inductor 1791 based on acurrent signal flowing through the detection terminals 1593 and 1594.The logic level of the detection voltage is varied with the frequency ofthe current signal, and may be increased with the increasing of thatfrequency and reduced with the decreasing of that frequency.

In some embodiments, when the signal is a high frequency signal, theinductive reactance of the inductor 1792 is quite high and so theinductor 1791 induces the detection voltage with a quite high logiclevel. When the signal is a low frequency signal or a DC signal, theinductive reactance of the inductor 1792 is quite low and so theinductor 1791 induces the detection voltage with a quite low logiclevel. One end of the inductor 1791 is grounded. The serially connectedcapacitor 1793 and resistor 1794 is connected in parallel with theinductor 1791 to receive the detection voltage generated by the inductor1791 and to filter a high frequency component of the detection voltageto generate a filtered detection voltage. The filtered detection voltagecharges the capacitor 1796 through the diode 1797 to generate a controlsignal 1795. Due to the diode 1797 providing a one-way charge for thecapacitor 1796, the logic level of control signal 1795 generated by thecapacitor 1796 is the maximum value of the detection voltage. Thecapacitor 1796 is coupled to the control end of the switch 1799. Firstand second ends of the switch 1799 are respectively coupled to theswitch terminals 1591 and 1592.

When the signal received by the detection terminals 1593 and 1594 is alow frequency signal or a DC signal, the control signal 1795 generatedby the capacitor 1796 is lower than the threshold voltage of the switch1799 and so the switch 1799 are conducted. At this time, the switchterminals 1591 and 1592 are shorted to bypass the external circuit(s)connected in parallel with the switch circuit 1790 b, such as at leastone capacitor in the terminal adapter circuits those show in FIGS.26A-C.

When the signal received by the detection terminal 1593 and 1594 is ahigh frequency signal, the control signal 1795 generated by thecapacitor 1796 is higher than the threshold voltage of the switch 1799and so the switch 1799 are cut off. At this time, the high frequencysignal is transmitted by the external circuit(s).

Hence, the ballast detection circuit 1790 can determine whether theinput signal is a high frequency AC signal provided by an electricballast. If yes, the high frequency AC signal is transmitted through theexternal circuit(s); if no, the input signal is transmitted through theswitch circuit 1790 b, bypassing the external circuit(s).

Next, exemplary embodiments of the conduction (bypass) and cut off (notbypass) operations of the switch circuit in the ballast detectioncircuit of an LED lamp will be illustrated. For example, the switchterminals 1591 and 1592 are coupled to a capacitor connected in serieswith the LED lamp, e.g., a signal for driving the LED lamp also flowsthrough the capacitor. The capacitor may be disposed inside the LED lampto be connected in series with internal circuit(s) or outside the LEDlamp to be connected in series with the LED lamp. When the lamp drivingcircuit 505 exists, the lamp driving circuit 505 provides a high voltageand high frequency AC driving signal as an external driving signal todrive the LED tube lamp 500. At this moment, the switch circuit of theballast detection circuit is cut off, and so the capacitor is connectedin series with an equivalent capacitor of the internal circuit(s) of theLED tube lamp for forming a capacitive voltage divider network. Thereby,a division voltage applied in the internal circuit(s) of the LED tubelamp is lower than the high voltage and high frequency AC drivingsignal, e.g.: the division voltage is in a range of 100-270V, and so noover voltage causes the internal circuit(s) damage. Alternatively, theswitch terminals 1591 and 1592 is coupled to the capacitor(s) of theterminal adapter circuit shown in FIGS. 26A-C to have the signal flowingthrough the half-wave node as well as the capacitor(s), e.g., thecapacitor 642 in FIG. 26A, or the capacitor 842 in FIG. 26C. When thehigh voltage and high frequency AC signal generated by the lamp drivingcircuit 505 is input, the switch circuit is cut off and so thecapacitive voltage divider is performed; and when the low frequency ACsignal of the commercial power or the direct current of battery isinput, the switch circuit bypasses the capacitor(s).

It is worth noting that the switch circuit may have plural switch unitsto have two or more switch terminals connecting in parallel with pluralparallel-connected capacitors (e.g., the capacitors 645 and 646 in FIG.26A, the capacitors 643, 645 and 646 in FIG. 26A, the capacitors 743 and744 or/and the capacitors 745 and 746 in FIG. 26B, the capacitors 843and 844 in FIG. 26C, the capacitors 845 and 846 in FIG. 26C, thecapacitors 842, 843 and 844 in FIG. 26C, the capacitors 842, 845 and 846in FIG. 26C, and the capacitors 842, 843, 844, 845 and 846 in FIG. 26C)to achieve the effect of bypassing the plural capacitors equivalentlyserial-connected with the LED tube lamp.

In addition, the ballast detection circuit of the present invention canbe used in conjunction with the mode switching circuits shown in FIGS.32A-32I. The switch circuit of the ballast detection circuit is replacedwith the mode switching circuit. The detection circuit of the ballastdetection circuit is coupled to one of the pins 501, 502, 503 and 504for detecting the signal input into the LED lamp through the pins 501,502, 503 and 504. The detection circuit generates a control signal tocontrol the mode switching circuit being at the first mode or the secondmode according to whether the signal is a high frequency, low frequencyor DC signal, i.e., the frequency of the signal.

For example, when the signal is a high frequency signal and higher thana defined mode switch frequency, such as the signal provided by the lampdriving circuit 505, the control signal generated by the detectioncircuit makes the mode switching circuit be at the second mode fordirectly inputting the filtered signal into the LED module. When thesignal is a low frequency signal or a direct signal and lower than thedefined mode switch frequency, such as the signal provided by thecommercial power or the battery, the control signal generated by thedetection circuit makes the mode switching circuit be at the first modefor directly inputting the filtered signal into the driving circuit.

FIG. 38A is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 35A, the present embodiment comprises two rectifyingcircuits 510 and 540, a filtering circuit 520, an LED lighting module530, two filament-simulating circuits 1560, and further comprises anauxiliary power module 2510. The auxiliary power module 2510 is coupledbetween the filtering output terminals 521 and 522. The auxiliary powermodule 2510 detects the filtered signal in the filtering outputterminals 521 and 522, and determines whether providing an auxiliarypower to the filtering output terminals 521 and 522 based on thedetected result. When the supply of the filtered signal is stopped or alogic level thereof is insufficient, i.e., when a drive voltage for theLED module is below a defined voltage, the auxiliary power moduleprovides auxiliary power to keep the LED lighting module 530 continuingto emit light. The defined voltage is determined according to anauxiliary power voltage of the auxiliary power module 2510. Thefilament-simulating circuits 1560 may be omitted and are thereforedepicted by dotted lines.

FIG. 38B is a block diagram of a power supply module in an LED tube lampaccording to an embodiment of the present invention. Compared to thatshown in FIG. 38A, the present embodiment comprises two rectifyingcircuits 510 and 540, a filtering circuit 520, an LED lighting module530, two filament-simulating circuits 1560, and an auxiliary powermodule 2510, and the LED lighting module 530 further comprises a drivingcircuit 1530 and an LED module 630. The auxiliary power module 2510 iscoupled between the driving output terminals 1521 and 1522. Theauxiliary power module 2510 detects the driving signal in the drivingoutput terminals 1521 and 1522, and determines whether to provide anauxiliary power to the driving output terminals 1521 and 1522 based onthe detected result. When the driving signal is no longer being suppliedor a logic level thereof is insufficient, the auxiliary power module2510 provides the auxiliary power to keep the LED module 630continuously light. The filament-simulating circuits 1560 may be omittedand are therefore depicted by dotted lines.

FIG. 38C is a schematic diagram of an auxiliary power module accordingto an embodiment of the present invention. The auxiliary power module2610 comprises an energy storage unit 2613 and a voltage detectioncircuit 2614. The auxiliary power module further comprises an auxiliarypower positive terminal 2611 and an auxiliary power negative terminal2612 for being respectively coupled to the filtering output terminals521 and 522 or the driving output terminals 1521 and 1522. The voltagedetection circuit 2614 detects a logic level of a signal at theauxiliary power positive terminal 2611 and the auxiliary power negativeterminal 2612 to determine whether releasing outward the power of theenergy storage unit 2613 through the auxiliary power positive terminal2611 and the auxiliary power negative terminal 2612.

In the present embodiment, the energy storage unit 2613 is a battery ora supercapacitor. When a voltage difference of the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612(the drive voltage for the LED module) is higher than the auxiliarypower voltage of the energy storage unit 2613, the voltage detectioncircuit 2614 charges the energy storage unit 2613 by the signal in theauxiliary power positive terminal 2611 and the auxiliary power negativeterminal 2612. When the drive voltage is lower than the auxiliary powervoltage, the energy storage unit 2613 releases the stored energy outwardthrough the auxiliary power positive terminal 2611 and the auxiliarypower negative terminal 2612.

The voltage detection circuit 2614 comprises a diode 2615, a bipolarjunction transistor (BJT) 2616 and a resistor 2617. A positive end ofthe diode 2615 is coupled to a positive end of the energy storage unit2613 and a negative end of the diode 2615 is coupled to the auxiliarypower positive terminal 2611. The negative end of the energy storageunit 2613 is coupled to the auxiliary power negative terminal 2612. Acollector of the BJT 2616 is coupled to the auxiliary power positiveterminal 2611, and an emitter thereof is coupled to the positive end ofthe energy storage unit 2613. One end of the resistor 2617 is coupled tothe auxiliary power positive terminal 2611 and the other end is coupledto a base of the BJT 2616. When the collector of the BJT 2616 is acut-in voltage higher than the emitter thereof, the resistor 2617conducts the BJT 2616. When the power source provides power to the LEDtube lamp normally, the energy storage unit 2613 is charged by thefiltered signal through the filtering output terminals 521 and 522 andthe conducted BJT 2616 or by the driving signal through the drivingoutput terminals 1521 and 1522 and the conducted BJT 2616 until that thecollector-emitter voltage of the BJT 2616 is lower than or equal to thecut-in voltage. When the filtered signal or the driving signal is nolonger being supplied or the logic level thereof is insufficient, theenergy storage unit 2613 provides power through the diode 2615 to keepthe LED lighting module 530 or the LED module 630 continuously light.

It is worth noting that in some embodiments, the maximum voltage of thecharged energy storage unit 2613 is at least one cut-in voltage of theBJT 2616 lower than the voltage difference applied between the auxiliarypower positive terminal 2611 and the auxiliary power negative terminal2612. The voltage difference provided between the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612 isa turn-on voltage of the diode 2615 lower than the voltage of the energystorage unit 2613. Hence, when the auxiliary power module 2610 providespower, the voltage applied at the LED module 630 is lower (about the sumof the cut-in voltage of the BJT 2616 and the turn-on voltage of thediode 2615). In the embodiment shown in the FIG. 38B, the brightness ofthe LED module 630 is reduced when the auxiliary power module suppliespower thereto. Thereby, when the auxiliary power module is applied to anemergency lighting system or a constant lighting system, the userrealizes the main power supply, such as commercial power, is abnormaland then performs necessary precautions therefor.

Referring to FIG. 39A, a block diagram of an LED tube lamp including apower supply module in accordance with certain embodiments isillustrated. Compared to the LED lamp shown in FIG. 24B, the LED tubelamp of FIG. 39A comprises two rectifying circuits 510 and 540, afiltering circuit 520, and an LED lighting module 530, and furthercomprises an installation detection module 2520. The installationdetection module 2520 is coupled to the rectifying circuit 510 (and/orthe rectifying circuit 540) via an installation detection terminal 2521and is coupled to the filtering circuit 520 via an installationdetection terminal 2522. The installation detection module 2520 detectsthe signal passing through the installation detection terminals 2521 and2522 and determines whether to cut off an LED driving signal (e.g., anexternal driving signal) passing through the LED tube lamp based on thedetected result. The installation detection module includes circuitryconfigured to perform these steps, and thus may be referred to as aninstallation detection circuit, or more generally as a detection circuitor cut-off circuit. When an LED tube lamp is not yet installed on a lampsocket or holder, or in some cases if it is not installed properly or isonly partly installed (e.g., one side is connected to a lamp socket, butnot the other side yet), the installation detection module 2520 detectsa smaller current and determines the signal is passing through a highimpedance. In this case, in certain embodiments, the installationdetection circuit 2520 is in a cut-off state to make the LED tube lampstop working. Otherwise, the installation detection module 2520determines that the LED tube lamp has already been installed on the lampsocket or holder, and it keeps on conducting to make the LED tube lampworking normally.

For example, in some embodiments, when a current passing through theinstallation detection terminals is greater than or equal to a specific,defined installation current (or a current value), which may indicatethat the current supplied to the lighting module 530 is greater than orequal to a specific, defined operating current, the installationdetection module is conductive to make the LED tube lamp operate in aconductive state. For example, a current greater than or equal to thespecific current value may indicate that the LED tube lamp has correctlybeen installed in the lamp socket or holder. When the current passingthrough the installation detection terminals is smaller than thespecific, defined installation current (or the current value), which mayindicate that the current supplied to the lighting module 530 is lessthan a specific, defined operating current, the installation detectionmodule cuts off current to make the LED tube lamp enter in anon-conducting state based on determining that the LED tube lamp hasbeen not installed in, or does not properly connect to, the lamp socketor holder. In certain embodiments, the installation detection module2520 determines conducting or cutting off based on the impedancedetection to make the LED tube lamp operate in a conducting state orenter non-conducting state. The LED tube lamp operating in a conductingstate may refer to the LED tube lamp including a sufficient currentpassing through the LED module to cause the LED light sources to emitlight. The LED tube lamp operating in a cut-off state may refer to theLED tube lamp including an insufficient current or no current passingthrough the LED module so that the LED light sources do not emit light.Accordingly, the occurrence of electric shock caused by touching theconductive part of the LED tube lamp which is incorrectly installed onthe lamp socket or holder can be better avoided.

Referring to FIG. 39B, a block diagram of an installation detectionmodule in accordance with certain embodiments is illustrated. Theinstallation detection module includes a switch circuit 2580, adetection pulse generating module 2540, a detection result latchingcircuit 2560, and a detection determining circuit 2570. Certain of thesecircuits or modules may be referred to as first, second, third, etc.,circuits as a naming convention to differentiate them from each other.

The detection determining circuit 2570 is coupled to and detects thesignal between the installation detection terminals 2521 (through aswitch circuit coupling terminal 2581 and the switch circuit 2580) and2522. It is also coupled to the detection result latching circuit 2560via a detection result terminal 2571 to transmit the detection resultsignal. The detection determining circuit 2570 may be configured todetect a current passing through terminals 2521 and 2522 (e.g., todetect whether the current is above or below a specific value).

The detection pulse generating module 2540 is coupled to the detectionresult latching circuit 2560 via a pulse signal output terminal 2541,and generates a pulse signal to inform the detection result latchingcircuit 2560 of a time point for latching (storing) the detectionresult. For example, the detection pulse generating module 2540 may be acircuit configured to generate a signal that causes a latching circuit,such as the detection result latching circuit 2560 to enter and remainin a state that corresponds to one of a conducting state or a cut-offstate for the LED tube lamp. The detection result latching circuit 2560stores the detection result according to the detection result signal (ordetection result signal and pulse signal), and transmits or provides thedetection result to the switch circuit 2580 coupled to the detectionresult latching circuit 2560 via a detection result latching terminal2561. The switch circuit 2580 controls the state between conducting orcut off between the installation detection terminals 2521 and 2522according to the detection result.

Referring to FIG. 39C, a block diagram of a detection pulse generatingmodule in accordance with certain embodiments is illustrated. Adetection pulse generating module 2640 may be a circuit that includesmultiple capacitors 2642, 2645, and 2646, multiple resistors 2643, 2647,and 2648, two buffers 2644, and 2651, an inverter 2650, a diode 2649,and an OR gate 2652. With use or operation, the capacitor 2642 and theresistor 2643 connect in series between a driving voltage (e.g., adriving voltage source, which may be a node of a power supply), such asVCC usually defined as a high logic level voltage, and a referencevoltage (or potential), such as ground potential in this embodiment. Theconnection node between the capacitor 2642 and the resistor 2643 iscoupled to an input terminal of the buffer 2644. The resistor 2647 iscoupled between the driving voltage, e.g., VCC, and an input terminal ofthe inverter 2650. The resistor 2648 is coupled between an inputterminal of the buffer 2651 and the reference voltage, e.g. groundpotential in this embodiment. An anode of the diode 2649 is grounded anda cathode thereof is coupled to the input terminal of the buffer 2651.First ends of the capacitors 2645 and 2646 are jointly coupled to anoutput terminal of the buffer 2644, and second, opposite ends of thecapacitors 2645 and 2646 are respectively coupled to the input terminalof the inverter 2650 and the input terminal of the buffer 2651. Anoutput terminal of the inverter 2650 and an output terminal of thebuffer 2651 are coupled to two input terminals of the OR gate 2652.According to certain embodiments, the voltage (or potential) for “highlogic level” and “low logic level” mentioned in this specification areall relative to another voltage (or potential) or a certain referencevoltage (or potential) in circuits, and further may be described as“logic high logic level” and “logic low logic level.”

When an end cap of an LED tube lamp is inserted into a lamp socket andthe other end cap thereof is electrically coupled to a human body, orwhen both end caps of the LED tube lamp are inserted into the lampsocket, the LED tube lamp is conductive with electricity. At thismoment, the installation detection module enters a detection stage. Thevoltage on the connection node of the capacitor 2642 and the resistor2643 is high initially (equals to the driving voltage, VCC) anddecreases with time to zero finally. The input terminal of the buffer2644 is coupled to the connection node of the capacitor 2642 and theresistor 2643, so the buffer 2644 outputs a high logic level signal atthe beginning and changes to output a low logic level signal when thevoltage on the connection node of the capacitor 2642 and the resistor2643 decreases to a low logic trigger logic level. As a result, thebuffer 2644 is configured to produce an input pulse signal and thenremain in a low logic level thereafter (stops outputting the input pulsesignal.) The width for the input pulse signal may be described as equalto one (initial setting) time period, which is determined by thecapacitance value of the capacitor 2642 and the resistance value of theresistor 2643.

Next, the operations for the buffer 2644 to produce the pulse signalwith the initial setting time period will be described below. Since thevoltage on a first end of the capacitor 2645 and on a first end of theresistor 2647 is equal to the driving voltage VCC, the voltage on theconnection node of both of them is also a high logic level. The firstend of the resistor 2648 is grounded and the first end of the capacitor2646 receives the pulse signal from the buffer 2644, so the connectionnode of the capacitor 2646 and the resistor 2648 has a high logic levelvoltage at the beginning but this voltage decreases with time to zero(in the meantime, the capacitor stores the voltage being equal to orapproaching the driving voltage VCC.) Accordingly, initially theinverter 2650 outputs a low logic level signal and the buffer 2651outputs a high logic level signal, and hence the OR gate 2652 outputs ahigh logic level signal (a first pulse signal) at the pulse signaloutput terminal 2541. At this moment, the detection result latchingcircuit 2560 stores the detection result for the first time according tothe detection result signal and the pulse signal. During that initialpulse time period, detection pulse generating module 2540 outputs a highlogic level signal, which results in the detection result latchingcircuit 2560 outputting the result of that high logic level signal.

When the voltage on the connection node of the capacitor 2646 and theresistor 2648 decreases to the low logic trigger logic level, the buffer2651 changes to output a low logic level signal to make the OR gate 2652output a low logic level signal at the pulse signal output terminal 2541(stops outputting the first pulse signal.) The width of the first pulsesignal output from the OR gate 2652 is determined by the capacitancevalue of the capacitor 2646 and the resistance value of the resistor2648.

The operation after the buffer 2644 stops outputting the pulse signal isdescribed as below. For example, the operation may be initially in anoperating stage. Since the capacitor 2646 stores the voltage beingalmost equal to the driving voltage VCC, and when the buffer 2644instantaneously changes its output from a high logic level signal to alow logic level signal, the voltage on the connection node of thecapacitor 2646 and the resistor 2648 is below zero but will be pulled upto zero by the diode 2649 rapidly charging the capacitor. Therefore, thebuffer 2651 still outputs a low logic level signal.

On the other hand, when the buffer 2644 instantaneously changes itsoutput from a high logic level signal to a low logic level signal, thevoltage on the one end of the capacitor 2645 also changes from thedriving voltage VCC to zero instantly. This makes the connection node ofthe capacitor 2645 and the resistor 2647 have a low logic level signal.At this moment, the output of the inverter 2650 changes to a high logiclevel signal to make the OR gate output a high logic level signal (asecond pulse signal.) The detection result latching circuit 2560 storesthe detection result for a second time according to the detection resultsignal and the pulse signal. Next, the driving voltage VCC charges thecapacitor 2645 through the resistor 2647 to make the voltage on theconnection node of the capacitor 2645 and the resistor 2647 increasewith time to the driving voltage VCC. When the voltage on the connectionnode of the capacitor 2645 and the resistor 2647 increases to reach ahigh logic trigger logic level, the inverter 2650 outputs a low logiclevel signal again to make the OR gate 2652 stop outputting the secondpulse signal. The width of the second pulse signal is determined by thecapacitance value of the capacitor 2645 and the resistance value of theresistor 2647.

As those mentioned above, in certain embodiments, the detection pulsegenerating module 2640 generates two high logic level pulse signals inthe detection stage, which are the first pulse signal and the secondpulse signal. These pulse signals are output from the pulse signaloutput terminal 2541. Moreover, there is an interval with a defined timebetween the first and second pulse signals (e.g., an opposite-logicsignal, which may have a low logic level when the pulse signals have ahigh logic level), and the defined time is determined by the capacitancevalue of the capacitor 2642 and the resistance value of the resistor2643).

From the detection stage entering the operating stage, the detectionpulse generating module 2640 does not produce the pulse signal any more,and keeps the pulse signal output terminal 2541 on a low logic levelpotential. As described herein, the operating stage is the stagefollowing the detection stage (e.g., following the time after the secondpulse signal ends). The operating stage occurs when the LED tube lamp isat least partly connected to a power source, such as provided in a lampsocket. For example, the operating stage may occur when part of the LEDtube lamp, such as only one side of the LED tube lamp, is properlyconnected to one side of a lamp socket, and part of the LED tube lamp iseither connected to a high impedance, such as a person, and/or isimproperly connected to the other side of the lamp socket (e.g., ismisaligned so that the metal contacts in the socket do not contact metalcontacts in the LED tube lamp). The operating stage may also occur whenthe entire LED tube lamp is properly connected to the lamp socket.

Referring to FIG. 39D, a detection determining circuit in accordancewith certain embodiments is illustrated. An exemplary detectiondetermining circuit 2670 includes a comparator 2671, and a resistor2672. A negative input terminal of the comparator 2671 receives areference logic level signal (or a reference voltage) Vref, a positiveinput terminal thereof is grounded through the resistor 2672 and is alsocoupled to a switch circuit coupling terminal 2581. Referring to FIGS.39B and 39D, the signal flowing into the switch circuit 2580 from theinstallation detection terminal 2521 outputs to the switch circuitcoupling terminal 2581 to the resistor 2672. When the current of thesignal passing through the resistor 2672 reaches a certain level (forexample, bigger than or equal to a defined current for installation,(e.g. 2 A) and this makes the voltage on the resistor 2672 higher thanthe reference voltage Vref (referring to two end caps inserted into thelamp socket,) the comparator 2671 produces a high logic level detectionresult signal and outputs it to the detection result terminal 2571. Forexample, when an LED tube lamp is correctly installed on a lamp socket,the comparator 2671 outputs a high logic level detection result signalat the detection result terminal 2571, whereas the comparator 2671generates a low logic level detection result signal and outputs it tothe detection result terminal 2571 when a current passing through theresistor 2672 is insufficient to make the voltage on the resistor 2672higher than the reference voltage Vref (referring to only one end capinserted into the lamp socket.) Therefore, in some embodiments, when theLED tube lamp is incorrectly installed on the lamp socket or one end capthereof is inserted into the lamp socket but the other one is groundedby an object such as a human body, the current will be too small to makethe comparator 2671 output a high logic level detection result signal tothe detection result terminal 2571.

Referring to FIG. 39E, a schematic detection result latching circuitaccording to some embodiments of the present invention is illustrated. Adetection result latching circuit 2660 includes a D flip-flop 2661, aresistor 2662, and an OR gate 2663. The D flip-flop 2661 has a CLK inputterminal coupled to a detection result terminal 2571, and a D inputterminal coupled to a driving voltage VCC. When the detection resultterminal 2571 first outputs a low logic level detection result signal,the D flip-flop 2661 initially outputs a low logic level signal at a Qoutput terminal thereof, but the D flip-flop 2661 outputs a high logiclevel signal at the Q output terminal thereof when the detection resultterminal 2571 outputs a high logic level detection result signal. Theresistor 2662 is coupled between the Q output terminal of the Dflip-flop 2661 and a reference voltage, such as ground potential. Whenthe OR gate 2663 receives the first or second pulse signals from thepulse signal output terminal 2541 or receives a high logic level signalfrom the Q output terminal of the D flip-flop 2661, the OR gate 2663outputs a high logic level detection result latching signal at adetection result latching terminal 2561. The detection pulse generatingmodule 2640 only in the detection stage outputs the first and the secondpulse signals to make the OR gate 2663 output the high logic leveldetection result latching signal, and thus the D flip-flop 2661 decidesthe detection result latching signal to be the high logic level or thelow logic level the rest of the time, e.g. including the operating stageafter the detection stage. Accordingly, when the detection resultterminal 2571 has no high logic level detection result signal, the Dflip-flop 2661 keeps a low logic level signal at the Q output terminalto make the detection result latching terminal 2561 also keep a lowlogic level detection result latching signal in the detection stage. Onthe contrary, once the detection result terminal 2571 has a high logiclevel detection result signal, the D flip-flop 2661 outputs and keeps ahigh logic level signal (e.g., based on VCC) at the Q output terminal.In this way, the detection result latching terminal 2561 keeps a highlogic level detection result latching signal in the operating stage aswell.

Referring to FIG. 39F, a schematic switch circuit according to someembodiments is illustrated. A switch circuit 2680 includes a transistor,such as a bipolar junction transistor (BJT) 2681, as being a powertransistor, which has the ability of dealing with high current/power andis suitable for the switch circuit. The BJT 2681 has a collector coupledto an installation detection terminal 2521, a base coupled to adetection result latching terminal 2561, and an emitter coupled to aswitch circuit coupling terminal 2581. When the detection pulsegenerating module 2640 produces the first and second pulse signals, theBJT 2681 is in a transient conduction state. This allows the detectiondetermining circuit 2670 to perform the detection for determining thedetection result latching signal to be a high logic level or a low logiclevel. When the detection result latching circuit 2660 outputs a highlogic level detection result latching signal at the detection resultlatching terminal 2561, the BJT 2681 is in the conducting state to makethe installation detection terminals 2521 and 2522 conducting. Incontrast, when the detection result latching circuit 2660 outputs a lowlogic level detection result latching signal at the detection resultlatching terminal 2561 and the output from detection pulse generatingmodule 2640 is a low logic level, the BJT 2681 is cut-off or in theblocking state to make the installation detection terminals 2521 and2522 cut-off or blocking.

Since the external driving signal is an AC signal and in order to avoidthe detection error resulting from the logic level of the externaldriving signal being just around zero when the detection determiningcircuit 2670 detects, the detection pulse generating module 2640generates the first and second pulse signals to let the detectiondetermining circuit 2670 perform two detections. So the issue of thelogic level of the external driving signal being just around zero in asingle detection can be avoided. In some cases, the time differencebetween the productions of the first and second pulse signals is notmultiple times of half one cycle of the external driving signal. Forexample, it does not correspond to the multiple phase differences of 180degrees of the external driving signal. In this way, when one of thefirst and second pulse signals is generated and unfortunately theexternal driving signal is around zero, it can be avoided that theexternal driving signal is again around zero when the other pulse signalis generated.

The time difference between the productions of the first and secondpulse signals, for example, an interval with a defined time between bothof them can be represented as following:the interval=(X+Y)(T/2),

where T represents the cycle of an external driving signal, X is anatural number, 0<Y<1, with Y in some embodiments in the range of0.05-0.95, and in some embodiments in the range of 0.15-0.85.

Furthermore, in order to avoid the installation detection moduleentering the detection stage from misjudgment resulting from the logiclevel of the driving voltage VCC being too small, the first pulse signalcan be set to be produced when the driving voltage VCC reaches or ishigher than a defined logic level. For example, in some embodiments, thedetection determining circuit 2670 works after the driving voltage VCCreaching a high enough logic level in order to prevent the installationdetection module from misjudgment due to an insufficient logic level.

According to the examples mentioned above, when one end cap of an LEDtube lamp is inserted into a lamp socket and the other one floats orelectrically couples to a human body or other grounded object, thedetection determining circuit outputs a low logic level detection resultsignal because of high impedance. The detection result latching circuitstores the low logic level detection result signal based on the pulsesignal of the detection pulse generating module, making it as the lowlogic level detection result latching signal, and keeps the detectionresult in the operating stage, without changing the logic value. In thisway, the switch circuit keeps cutting-off or blocking instead ofconducting continually. And further, the electric shock situation can beprevented and the requirement of safety standard can also be met. On theother hand, when two end caps of the LED tube lamp are correctlyinserted into the lamp socket, the detection determining circuit outputsa high logic level detection result signal because the impedance of thecircuit for the LED tube lamp itself is small. The detection resultlatching circuit stores the high logic level detection result signalbased on the pulse signal of the detection pulse generating module,making it as the high logic level detection result latching signal, andkeeps the detection result in the operating stage. So the switch circuitkeeps conducting to make the LED tube lamp work normally in theoperating stage.

In some embodiments, when one end cap of the LED tube lamp is insertedinto the lamp socket and the other one floats or electrically couples toa human body, the detection determining circuit outputs a low logiclevel detection result signal to the detection result latching circuit,and then the detection pulse generating module outputs a low logic levelsignal to the detection result latching circuit to make the detectionresult latching circuit output a low logic level detection resultlatching signal to make the switch circuit cutting-off or blocking. Assuch, the switch circuit blocking makes the installation detectionterminals, e.g. the first and second installation detection terminals,blocking. As a result, the LED tube lamp is in non-conducting orblocking state.

However, in some embodiments, when two end caps of the LED tube lamp arecorrectly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level detection result signal to thedetection result latching circuit to make the detection result latchingcircuit output a high logic level detection result latching signal tomake the switch circuit conducting. As such, the switch circuitconducting makes the installation detection terminals, e.g. the firstand second installation detection terminals, conducting. As a result,the LED tube lamp operates in a conducting state.

Thus, according to the operation of the installation detection module, afirst circuit, upon connection of at least one end of the LED tube lampto a lamp socket, generates and outputs two pulses, each having a pulsewidth, with a time period between the pulses. The first circuit mayinclude various of the elements described above configured to output thepulses to a base of a transistor (e.g., a BJT transistor) that serves asa switch. The pulses occur during a detection stage for detectingwhether the LED tube lamp is properly connected to a lamp socket. Thetiming of the pulses may be controlled based on the timing of variousparts of the first circuit changing from high to low logic levels, orvice versa.

The pulses can be timed such that, during that detection stage time, ifthe LED tube lamp is properly connected to the lamp socket (e.g., bothends of the LED tube lamp are correctly connected to conductiveterminals of the lamp socket), at least one of the pulse signals occurswhen an AC current from a driving signal is at a non-zero level. Forexample, the pulse signals can occur at intervals that are differentfrom half of the period of the AC signal. For example, respective startpoints or mid points of the pulse signals, or a time between an end ofthe first pulse signal and a beginning of the second pulse signal may beseparated by an amount of time that is different from half of the periodof the AC signal (e.g., it may be between 0.05 and 0.95 percent of amultiple of half of the period of the AC signal). During a pulse thatoccurs when the AC signal is at a non-zero level, a switch that receivesthe AC signal at the non-zero level may be turned on, causing a latchcircuit to change states such that the switch remains permanently on solong as the LED tube lamp remains properly connected to the lamp socket.For example, the switch may be configured to turn on when each pulse isoutput from the first circuit. The latch circuit may be configured tochange state only when the switch is on and the current output from theswitch is above a threshold value, which may indicate a properconnection to a light socket. As a result, the LED tube lamp operates ina conducting state.

On the other hand, if both pulses occur when a driving signal at the LEDtube lamp has a near-zero current level, or a current level below aparticular threshold, then the state of the latch circuit is notchanged, and so the switch is only on during the two pulses, but thenremains permanently off after the pulses and after the detection mode isover. For example, the latch circuit can be configured to remain in itspresent state if the current output from the switch is below thethreshold value. In this manner, the LED tube lamp remains in anon-conducting state, which prevents electric shock, even though part ofthe LED tube lamp is connected to an electrical power source.

It is worth noting that according to certain embodiments, the width ofthe pulse signal generated by the detection pulse generating module isbetween 10 μs to 1 ms, and it is used to make the switch circuitconducting for a short period when the LED tube lamp conductsinstantaneously. In some embodiments, a pulse current is generated topass through the detection determining circuit for detecting anddetermining. Since the pulse is for a short time and not for a longtime, the electric shock situation will not occur. Furthermore, thedetection result latching circuit also keeps the detection result duringthe operating stage (e.g., the operating stage being the period afterthe detection stage and during which part of the LED tube lamp is stillconnected to a power source), and no longer changes the detection resultstored previously complying with the circuit state changing. A situationresulting from changing the detection result can thus be avoided. Insome embodiments, the installation detection module, such as the switchcircuit, the detection pulse generating module, the detection resultlatching circuit, and the detection determining circuit, could beintegrated into a chip and then embedded in circuits for saving thecircuit cost and layout space.

As discussed in the above examples, in some embodiments, an LED tubelamp includes an installation detection circuit comprising a firstcircuit configured to output two pulse signals, the first pulse signaloutput at a first time and the second pulse signal output at a secondtime after the first time, and a switch configured to receive an LEDdriving signal and to receive the two pulse signals, wherein the twopulse signals control turning on and off of the switch. The installationdetection circuit may be configured to, during a detection stage, detectduring each of the two pulse signals whether the LED tube lamp isproperly connected to a lamp socket. When it is not detected duringeither pulse signal that the LED tube lamp is properly connected to thelamp socket, the switch may remain in an off state after the detectionstage. When it is detected during at least one of the pulse signals thatthe LED tube lamp is properly connected to the lamp socket, the switchmay remain in an on state after the detection stage. The two pulsesignals may occur such that they are separated by a time different froma multiple of half of a period of the LED driving signal, and such thatat least one of them does not occur when the LED driving signal has acurrent value of substantially zero. It should be noted that although acircuit for producing two pulse signals is described, the disclosure isnot intended to be limiting as such. For example, a circuit may beimplemented such that a plurality of pulse signals may occur, wherein atleast two of the plurality of pulse signals are separated by a timedifferent from a multiple of half of a period of the LED driving signal,and such that at least one of the plurality of pulse signals does notoccur when the LED driving signal has a current value of substantiallyzero.

For example, according to the design of the power supply in someembodiments, the circuit board assembly has a long circuit sheet and ashort circuit board that are adhered to each other with the shortcircuit board being adjacent to the side edge of the long circuit sheet.The short circuit board may be provided with power supply module to formthe power supply, and may include the installation detection module.

According to the design of the power supply module, the external drivingsignal may be a low frequency AC signal (e.g., commercial power), a highfrequency AC signal (e.g., that provided by an electronic ballast), or aDC signal (e.g., that provided by a battery or external configureddriving source), input into the LED tube lamp through a drivearchitecture of dual-end power supply. For the drive architecture ofdual-end power supply, the external driving signal may be input by usingonly one end thereof as single-end power supply.

The LED tube lamp may omit the rectifying circuit in the power supplymodule when the external driving signal is a DC signal.

According to the design of the rectifying circuit in the power supplymodule, there may be a dual rectifying circuit. First and secondrectifying circuits of the dual rectifying circuit are respectivelycoupled to the two end caps disposed on two ends of the LED tube lamp.The dual rectifying circuit is applicable to the drive architecture ofdual-end power supply. Furthermore, the LED tube lamp having at leastone rectifying circuit is applicable to the drive architecture of a lowfrequency AC signal, high frequency AC signal or DC signal.

The dual rectifying circuit may comprise, for example, two half-waverectifier circuits, two full-wave bridge rectifying circuits or onehalf-wave rectifier circuit and one full-wave bridge rectifying circuit.

According to the design of the pin in the LED tube lamp, there may betwo pins in single end (the other end has no pin), two pins incorresponding ends of two ends, or four pins in corresponding ends oftwo ends. The designs of two pins in single end and two pins incorresponding ends of two ends are applicable to a signal rectifyingcircuit design of the rectifying circuit. The design of four pins incorresponding ends of two ends is applicable to a dual rectifyingcircuit design of the rectifying circuit, and the external drivingsignal can be received by two pins in only one end or any pin in each oftwo ends.

According to the design of the filtering circuit of the power supplymodule, there may be a single capacitor, or π filter circuit. Thefiltering circuit filers the high frequency component of the rectifiedsignal for providing a DC signal with a low ripple voltage as thefiltered signal. The filtering circuit also further comprises the LCfiltering circuit having a high impedance for a specific frequency forconforming to current limitations in specific frequencies of the ULstandard. Moreover, the filtering circuit according to some embodimentsfurther comprises a filtering unit coupled between a rectifying circuitand the pin(s) for reducing the EMI resulted from the circuit(s) of theLED tube lamp. The LED tube lamp may omit the filtering circuit in thepower supply module when the external driving signal is a DC signal.

According to the design of the LED lighting module in some embodiments,the LED lighting module may comprise the LED module and the drivingcircuit or only the LED module. The LED module may be connected with avoltage stabilization circuit in parallel for preventing the LED modulefrom over voltage. The voltage stabilization circuit may be a voltageclamping circuit, such as zener diode, DIAC and so on. When therectifying circuit has a capacitive circuit, in some embodiments, twocapacitors are respectively coupled between two corresponding pins intwo end caps and so the two capacitors and the capacitive circuit as avoltage stabilization circuit perform a capacitive voltage divider.

If there are only the LED module in the LED lighting module and theexternal driving signal is a high frequency AC signal, a capacitivecircuit (e.g., having at least one capacitor) is in at least onerectifying circuit and the capacitive circuit is connected in serieswith a half-wave rectifier circuit or a full-wave bridge rectifyingcircuit of the rectifying circuit and serves as a current modulationcircuit (or a current regulator) to modulate or to regulate the currentof the LED module due to that the capacitor equates a resistor for ahigh frequency signal. Thereby, even different ballasts provide highfrequency signals with different voltage logic levels, the current ofthe LED module can be modulated into a defined current range forpreventing overcurrent. In addition, an energy-releasing circuit isconnected in parallel with the LED module. When the external drivingsignal is no longer supplied, the energy-releasing circuit releases theenergy stored in the filtering circuit to lower a resonance effect ofthe filtering circuit and other circuits for restraining the flicker ofthe LED module. In some embodiments, if there are the LED module and thedriving circuit in the LED lighting module, the driving circuit may be abuck converter, a boost converter, or a buck-boost converter. Thedriving circuit stabilizes the current of the LED module at a definedcurrent value, and the defined current value may be modulated based onthe external driving signal. For example, the defined current value maybe increased with the increasing of the logic level of the externaldriving signal and reduced with the reducing of the logic level of theexternal driving signal. Moreover, a mode switching circuit may be addedbetween the LED module and the driving circuit for switching the currentfrom the filtering circuit directly or through the driving circuitinputting into the LED module.

A protection circuit may be additionally added to protect the LEDmodule. The protection circuit detects the current and/or the voltage ofthe LED module to determine whether to enable corresponding over currentand/or over voltage protection.

According to the design of the ballast detection circuit of the powersupply module, the ballast detection circuit is substantially connectedin parallel with a capacitor connected in series with the LED module anddetermines the external driving signal whether flowing through thecapacitor or the ballast detection circuit (i.e., bypassing thecapacitor) based on the frequency of the external driving signal. Thecapacitor may be a capacitive circuit in the rectifying circuit.

According to the design of the filament-simulating circuit of the powersupply module, there may be a single set of a parallel-connectedcapacitor and resistor, two serially connected sets, each having aparallel-connected capacitor and resistor, or a negative temperaturecoefficient circuit. The filament-simulating circuit is applicable toprogram-start ballast for avoiding the program-start ballast determiningthe filament abnormally, and so the compatibility of the LED tube lampwith program-start ballast is enhanced. Furthermore, thefilament-simulating circuit almost does not affect the compatibilitiesfor other ballasts, e.g., instant-start and rapid-start ballasts.

According to the design of the ballast-compatible circuit of the powersupply module in some embodiments, the ballast-compatible circuit can beconnected in series with the rectifying circuit or connected in parallelwith the filtering circuit and the LED lighting module. Under the designof being connected in series with the rectifying circuit, theballast-compatible circuit is initially in a cutoff state and thenchanges to a conducting state in an objective delay. Under the design ofbeing connected in parallel with the filtering circuit and the LEDlighting module, the ballast-compatible circuit is initially in aconducting state and then changes to a cutoff state in an objectivedelay. The ballast-compatible circuit makes the electronic ballastreally activate during the starting stage and enhances the compatibilityfor instant-start ballast. Furthermore, the ballast-compatible circuitalmost does not affect the compatibilities with other ballasts, e.g.,program-start and rapid-start ballasts.

According to the design of the auxiliary power module of the powersupply module, the energy storage unit may be a battery or asupercapacitor, connected in parallel with the LED module. The auxiliarypower module is applicable to the LED lighting module having the drivingcircuit.

According to the design of the LED module of the power supply module,the LED module comprises plural strings of LEDs connected in parallelwith each other, wherein each LED may have a single LED chip or pluralLED chips emitting different spectrums. Each LEDs in different LEDstrings may be connected with each other to form a mesh connection.

In other words, the abovementioned features can be implemented in anycombination to improve the LED tube lamp.

As shown in FIG. 19, in some embodiments, the LED light strip 2 and thepower supply 5 may be connected by utilizing the circuit board assembly25 instead of soldering bonding. The long circuit sheet 251 and theshort circuit board 253 are adhered to each other with the short circuitboard 253 being adjacent to the side edge of the long circuit sheet 251.And then, the power supply module 250 is electrically connected to thewiring layer 2 a of the LED light strip 2. Besides, the LED light strip2 as mentioned before is not limited to one-layered or two-layeredcircuit board, and it could be the circuit board shown in FIG. 23further including another wiring layer 2 c. The LED light source 202 isconfigured on the wiring layer 2 a and electrically connected to thepower supply 5 through the wiring layer 2 a. As shown in FIG. 20, insome embodiments, the circuit board assembly 25 has the long circuitsheet 251 and the short circuit board 253, and the long circuit sheet251 could be the bendable circuit sheet of the LED light strip 2including the wiring layer 2 a and the dielectric layer 2 b. Thedielectric layer 2 b and the short circuit board 253 are fixed by ajoint manner, and then the wiring layer 2 a is adhered to the dielectriclayer 2 b and extends to the short circuit board 253. The embodimentsmentioned above do not depart from the scope of and are all included inthe applications of the circuit board assembly 25 of the presentinvention.

In the embodiments mentioned above, the short circuit board 253 may havea length generally of about 15 mm to about 40 mm and may be about 19 mmto about 36 mm, while the long circuit sheet 251 may have a lengthgenerally of about 800 mm to about 2800 mm and may be about 1200 mm toabout 2400 mm. In some embodiments, a ratio of the length of the shortcircuit board 253 to the length of the long circuit sheet 251 rangesfrom about 1:20 to about 1:200.

In addition, in some abovementioned embodiments, when the LED lightstrip 2 and the power supply 5 are fixed by soldering bonding but theLED light strip 2 is not mounted onto the inner circumferential surfaceof the LED tube lamp 1, the LED light strip 2 may not safely fix andsupport the power supply 5. Moreover, in some embodiments, when thepower supply 5 has to be fixed in the end cap of the end region of theLED tube lamp 1, the end cap would be relatively longer and then reducesthe effectively emitting area of the LED tube lamp 1.

Referring to FIG. 22, in some embodiments, the LED light strip 2 adoptsa hard circuit board 22 made of aluminum and the end thereof can berelatively fixed onto the end region of the LED tube lamp 1.Furthermore, for the sake of the implementation of soldering bonding andthe length of the end cap 3 being able to be reduced since it is nolonger required to have enough space to contain the entire length of thepower supply 5, the power supply 5 is perpendicularly adhered to thehard circuit board 22 made of aluminum via soldering. By doing so, theeffectively emitting area of the LED tube lamp 1 increases. Also, in theabovementioned embodiments, the power supply 5 solders a metal wire forelectrically connecting to the conductive pin 301 of the end cap 3 inaddition to configuring the power supply module 250. In someembodiments, the conductive lead 53 of the power supply module 250 onthe power supply 5 could be directly used to electrically connect to theend cap 3, and the metal wire mentioned above is unnecessary any more soas to simplify the manufacture process.

In the embodiments of the present invention, a safety switch isconfigured in the end cap for preventing leakage current and it connectsthe conductive pin 301 to the power supply. When the LED tube lamp iscorrectly installed into the lamp socket, the safety switch is justtriggered (the power supply being electrically connected to theconductive pin 301). In this way, the end cap does not conductelectricity before the LED tube lamp is correctly installed into thelamp socket. And this provides the safety protection to the user forpreventing the user from electric shock in case that one end of the LEDtube lamp is inserted into the lamp socket but the other end is touchedby the user's hand. In some embodiments of the present invention, thesafety switch is a logic level switch triggered only through the LEDtube lamp being correctly installed. And when the logic level switch istriggered (liquid flows to a preset position), the LED tube lamp worksnormally.

In some embodiments, two safety switches are respectively configuredinto the end caps on both ends of the LED tube lamp. Or, only one safetyswitch is configured with, in this case, the end cap configured with thesafety switch may be marked for reminding the user of firstly installinganother unmarked end cap.

Referring to FIG. 41, a schematic structure of an LED tube lampaccording to some embodiments of the present invention is illustrated.An LED tube lamp 100 includes a lamp tube 1 and two end caps 3 (theproportion of the end cap 3 in relation to the lamp tube 1 schematizedin FIG. 41 is exaggerated in order to highlight the structure of the endcap 3. In an embodiment, the depth of the end cap 3 is from 9 to 70 mm.The axial length of the lamp tube 1 is from 254 to 2000 mm, that is,from 1 inch to 8 inches.) The end caps 3 are respectively configured atthe both ends of the lamp tube 1. The end cap 3 includes an electricallyconductive pin 301, an actuator 332, a micro switch 334, and a powersupply 5. When the LED tube lamp 100 is correctly installed into thelamp socket (not shown), the actuator 332 triggers the micro switch 334for allowing the power supply 5 to electrically connect to commercialelectricity so as to light up the LED components (not shown) in the LEDtube lamp 100.

For one of the variations of the micro switch mentioned above, as shownin FIG. 42, an input terminal 3341 and an output terminal 3343 areelectrically connected to a hollow conductive pin (not shown) and apower supply 5 (not shown), correspondingly. A bidirectional triodethyristor (TRIAC) 3345 is configured between the input terminal 3341 andthe output terminal 3343, a resistor 3347 is electrically coupled to aa1 end of the micro switch 334 having a a2 end electrically coupled to atrigger terminal of the TRIAC 3345. In one embodiment, the resistance ofthe resistor 3347 is from 1 Ohm to 10K Ohm, and in some cases, about 2KOhm. The current passing through the micro switch 334 decreases from 10A before deformation to about 0.1 A. Accordingly, a wider range isprovided for selecting the micro switch and the cost is further down.

The safety switch could replace the resistor 3347 with a siliconcontrolled rectifier, SCR; i.e., the safety switch includes the SCR, theTRIAC 3345, and the micro switch 334, and wherein the micro switch 334could be any micro switch in the embodiments mentioned above. In oneembodiment, the input terminal 3341 of the safety switch is electricallyconnected to any hollow conductive pin (not shown) of the LED tube lamp,and the output terminal 3343 thereof is electrically connected to thepower supply 5. The both ends of the TRIAC 3345 are electrically coupledto the input terminal 3341 and the output terminal 3343, respectively.Further, the SCR is electrically coupled to the micro switch 334 inserial. One end of the serially connected SCR and the micro switch 334is electrically coupled to the control terminal of the TRIAC 3345, theother end of the serially connected SCR and the micro switch 334 iselectrically coupled to the input terminal 3341.

When the micro switch 334 opens, the control terminal of the TRIAC 3345is not coupled to the input terminal 3341. Meanwhile, the TRIAC 3345 isin a cutoff state so as to make the hollow conductive pin beinguncoupled to the power supply 5. When the micro switch 334 is triggeredand shorted, the current is transmitted from the input terminal 3341,the serially connected SCR and the micro switch 334 to the controlterminal of the TRIAC 3345 to make the TRIAC 3345 being triggered andconducted. Therefore, the hollow conductive pin 301 is coupled to thepower supply 5 to make the LED tube lamp working normally.

In the abovementioned embodiments with the safety switch by using themicro switch 334 only, an enormous transient current, such as biggerthan 10 A, is inrushing to flow through the micro switch 334, the powersupply 5, and the LED components when the micro switch 334 is instantlytriggered. Therefore, not only does the micro switch 334 use a higherwithstanding current, but the volume thereof also gets bigger. Further,the transient current may damage the power supply 5 and the LEDcomponents. However, in some embodiments, the transient current could berestrained by the SCR or the resistor 3347 so as to lower thewithstanding current used by the micro switch 334, and simultaneously,the volume of the micro switch 334 and the cost are both down. In thisway, the current passing through the micro switch could be down to about0.1 A.

Next, the structure of the end cap with safety switch will be describedin more detail as below.

Turning to FIG. 40A, in accordance with an exemplary embodiment of thepresent invention, the end cap 3 includes a housing 300; a power supply(not shown); an electrically conductive pin 301 extending outwardly froma top wall of the housing 300; an actuator 332 movably connected to thehousing; and a micro switch 334. The upper portion of the actuator 332projects out of an opening formed in the top wall of the housing 300.The actuator 332 includes, inside the housing 300, a stopping flange 337extending radially from its intermediary portion and a shaft 335extending axially in its lower portion. The shaft 335 is movablyconnected to a base 336 rigidly mounted inside the housing 300. Apreloaded coil spring 333 is retained, around the shaft 335, between thestopping flange 337 and the base 336. An aperture is provided in theupper portion of the actuator 332 through which the electricallyconductive pin 301 is arranged. The micro switch 334 is positionedinside the housing 300 to be actuated by the shaft 335 at apredetermined actuation point. The micro switch 334, when actuated,makes the circuit, directly or through a relay, between the electricallyconnective pin 301 and the power supply 5. The actuator 332 is alignedwith the electrically conductive pin 301, the opening in the top wall ofthe housing 300 and the coil spring 333 along the longitudinal axis ofthe lamp tube 1 to be reciprocally movable between the top wall of thehousing 300 and the base 336. When the electrically conductive pin 301is unplugged from the socket, the coil spring 333 biases the actuator332 to its rest position until the stopping flange 337 is urged againstthe top wall of the housing 300. The micro switch 334 stays off and thecircuit of the LED tube lamp stays open. When the electricallyconductive pin 301 is duly plugged into the socket on a lamp holder, theactuator 332 is depressed and brings the shaft 335 to the actuationpoint. The micro switch 334 is turned on to, directly or through arelay, complete the circuit of the LED tube lamp.

In some embodiments, two end caps of the LED tube lamp according to theembodiments of the present invention may configure two micro switches,correspondingly. In this way, the hurt resulting from leaking current tothe user can be avoided when the LED tube lamp is in installation.

When the LED tube lamp is not inserted the lamp socket, the actuator 333moves forward outside of the housing 300 because of the tension of thecoil spring 333. Hence, the micro switch 334 opens to make the powersupply 5 disconnect the conductive pin 301.

Turning to FIG. 40B, in accordance with an exemplary embodiment of thepresent invention, the end cap 3 includes a housing 300; a power supply(not shown); an electrically conductive pin 301 a extending outwardlyfrom a top wall of the housing 300; an actuator 332 movably connected tothe housing; and a micro switch 334. In an embodiment, the electricallyconductive pin 301 a is an enlarged hollow structure. The upper portionof the actuator 332 is bowl-shaped to receive the electricallyconductive pin 301 a and projects out of an opening formed in the topwall of the housing 300. The actuator 332 includes, inside the housing300, a stopping flange 337 extending radially from its intermediaryportion and, in its lower portion, a spring retainer and a bulging part338. A preloaded coil spring 333 is retained between the string retainerand a base 336 rigidly mounted inside the housing 300. The micro switch334 is positioned inside the housing 300 to be actuated by the bulgingpart 338 at a predetermined actuation point. The micro switch 334, whenactuated, makes the circuit, directly or through a relay, between theelectrically conductive pin 301 a and the power supply. The actuator 332is aligned with the electrically conductive pin 301 a, the opening inthe top wall of the housing 300 and the coil spring 333 along thelongitudinal axis of the lamp tube 1 to be reciprocally movable betweenthe top wall of the housing 300 and the base 336. When the electricallyconductive pin 301 a is unplugged from the socket of a lamp holder, thecoil spring 333 biases the actuator 332 to its rest position until thestopping flange 337 is urged against the top wall of the housing 300.The micro switch 334 stays off and the circuit of the LED tube lamp 1stays open. When the electrically conductive pin 301 a is duly pluggedinto the socket on the lamp holder, the actuator 332 is depressed andbrings the bulging part 338 to the actuation point. The micro switch 334is turned on to, directly or through a relay, complete the circuit.

In some embodiments, two end caps of the LED tube lamp according to theembodiments of the present invention may configure two micro switches,correspondingly. In some embodiments, the actuator 332 is intermittentlyput around the conductive pin 301 a.

When the LED tube lamp is not inserted the lamp socket, the actuator 333moves forward outside of the housing 300 because of the tension of thecoil spring 333. Hence, the micro switch 334 opens to make the powersupply 5 disconnect the conductive pin 301 a.

Turning to FIG. 40C, in accordance with an exemplary embodiment of thepresent invention, the end cap 3 includes a housing 300; a power supply(not shown); an electrically conductive pin 301 extending outwardly froma top wall of the housing 300; an actuator 332 movably connected to thehousing; and a micro switch 334. In an embodiment, the end cap includesa pair of electrically conductive pins 301. The upper portion of theactuator 332 projects out of an opening formed in the top wall of thehousing 300. The actuator 332 includes, inside the housing 300, astopping flange 337 extending radially from its intermediary portion anda spring retainer in its lower portion. A first coil spring 333 a,preloaded, is retained between the string retainer and a first end ofthe micro switch 334. A second coil spring 333 b, also preloaded, isretained between a second end of the micro switch 334 and a base rigidlymounted inside the housing. Both of the springs 333 a, 333 b are chosento respond to a gentle depression; however, the first coil spring 333 ais chosen to have a different stiffness than the second coil spring 333b. In some embodiments, the first coil spring 333 a reacts to adepression of from 0.5 to 1 N but the second coil spring 333 b reacts toa depression of from 3 to 4 N. The actuator 332 is aligned with theopening in the top wall of the housing 300, the micro switch 334 and theset of coil springs 333 a, 333 b along the longitudinal axis of the lamptube to be reciprocally movable between the top wall of the housing 300and the base. The micro switch 334, sandwiched between the first coilspring 333 a and the second coil spring 333 b, is actuated when thefirst coil spring 333 a is compressed to a predetermined actuationpoint. The micro switch 334, when actuated, makes the circuit, directlyor through a relay, between the pair of electrically conductive pins 301and the power supply. When the pair of electrically conductive pins 301are unplugged from the socket on a lamp holder, the pair of coil springs333 a, 333 b bias the actuator 332 to its rest position until thestopping flange 337 is urged against the top wall of the housing 300.The micro switch 334 stays off and the circuit of the LED tube lampstays open. When the pair of electrically conductive pins 301 are dulyplugged into the socket on a lamp holder, the actuator 332 is depressedand compresses the first coil spring 333 a to the actuation point. Themicro switch 334 is turned on to, directly or through a relay, completethe circuit.

In some embodiments, two end caps of the LED tube lamp according to theembodiments of the present invention may configure two micro switches,correspondingly. In this way, the hurt resulting from leaking current tothe user can be avoided when the LED tube lamp is in installation. Sincethe LED tube lamp has correctly been installed and the micro switch hasbeen actuated, the connection between the conductive pin 301 and thepower supply is just implemented.

When the LED tube lamp is not inserted the lamp socket, the actuator 333moves forward outside of the housing 300 because of the tension of thecoil spring 333. Hence, the micro switch 334 opens to make the powersupply 5 disconnect the conductive pin 301 a.

Turning to FIG. 40D, in accordance with an exemplary embodiment of thepresent invention, the end cap 3 includes a housing 300; a power supply(not shown); an electrically conductive pin 301 extending outwardly froma top wall of the housing 300; an actuator 332 movably connected to thehousing; a first contact element 334 a; and a second contact element338. The upper portion of the actuator 332 projects out of an openingformed in the top wall of the housing 300. The actuator 332 includes,inside the housing 300, a stopping flange extending radially from itsintermediary portion and a shaft 335 extending axially in its lowerportion. The shaft 335 is movably connected to a base 336 rigidlymounted inside the housing 300. A preloaded coil spring 333 is retained,around the shaft 335, between the stopping flange and the base 336. Anaperture is provided in the upper portion of the actuator 332 throughwhich the electrically conductive pin 301 is arranged. The actuator 332is aligned with the electrically conductive pin 301, the opening in thetop wall of the housing 300, the coil spring 333 and the first andsecond contact elements 334 a, 338 along the longitudinal axis of thelamp tube to be reciprocally movable between the top wall of the housing300 and the base 336. The first contact element 334 a includes aplurality of metallic pieces, which are spaced apart from one another,and is configured to form a flexible female-type receptacle, e.g.V-shaped or bell-shaped. The first contact element 334 a is made fromcopper or copper alloy. The second contact element 338 is positioned onthe shaft 335 to, when the shaft 335 moves downwards, come into thefirst contact element 334 a and electrically connect the plurality ofmetallic pieces at a predetermined actuation point. The first contactelement 334 a is configured to impart a spring-like bias on the secondcontact element 338 when the second contact element 338 goes into thefirst contact element 334 a to ensure faithful electrical connectionwith one another. The first and second contact elements 334 a, 338 aremade from, in some embodiments, copper alloy. When the electricallyconductive pin 301 is unplugged from the socket, the coil spring 333biases the actuator 332 to its rest position until the stopping flangeis urged against the top wall of the housing 300. The first and secondcontact elements 334 a, 338 stay unconnected and the circuit of the LEDtube lamp stays open. When the electrically conductive pin 301 is dulyplugged into the socket on a lamp holder, the actuator 332 is depressedand brings the second contact element 338 to the actuation point. Thefirst and second contact elements 334 a, 338 are connected to, directlyor through a relay, complete the circuit of the LED tube lamp.

In some embodiments, two end caps of the LED tube lamp according to theembodiments of the present invention may configure two micro switches,correspondingly. In this way, the hurt resulting from leaking current tothe user can be avoided when the LED tube lamp is in installation.

When the LED tube lamp is not inserted the lamp socket, the actuator 333moves forward outside of the housing 300 because of the tension of thecoil spring 333. Hence, the micro switch 334 opens to make the powersupply 5 disconnect the conductive pin 301 a.

Turning to FIG. 40E, in accordance with an exemplary embodiment of thepresent invention, the end cap 3 includes a housing 300; a power supply(not shown); an electrically conductive pin 301 extending outwardly froma top wall of the housing 300; an actuator 332 movably connected to thehousing; a first contact element 334 a; and a second contact element.The upper portion of the actuator 332 projects out of an opening formedin the top wall of the housing 300. The actuator 332 includes, insidethe housing 300, a stopping flange extending radially from itsintermediary portion and a shaft 335 extending axially in its lowerportion. The shaft 335 is movably connected to a base rigidly mountedinside the housing 300. A preloaded coil spring 333 is retained, aroundthe shaft 335, between the stopping flange and the base. The actuator332 is aligned with the electrically conductive pin 301, the opening inthe top wall of the housing 300, the coil spring 333, the first contactelement 334 a and the second contact element along the longitudinal axisof the lamp tube to be reciprocally movable between the top wall of thehousing 300 and the base. In some embodiments, the first contact element334 a forms an integral and flexible female-type receptacle and is madefrom, copper, copper alloy or both. The second contact element, madefrom, copper, copper alloy or both, is fixedly disposed inside thehousing 300. In an embodiment, the second contact element is fixedlydisposed on the power supply 5. The first contact element 334 a isattached to the lower end of the shaft 335 to, when the shaft 335 movesdownwards, receive and electrically connect the second contact elementat a predetermined actuation point. The first contact element 334 a isconfigured to impart a spring-like bias on the second contact elementwhen the former receives the latter to ensure faithful electricalconnection with each other. When the electrically conductive pin 301 isunplugged from the socket on a lamp holder, the coil spring 333 biasesthe actuator 332 to its rest position until the stopping flange is urgedagainst the top wall of the housing 300. The first contact element 334 aand the second contact element stay unconnected and the circuit of theLED tube lamp stays open. When the electrically conductive pin 301 isduly plugged into the socket, the actuator 332 is depressed and bringsthe first contact element 334 a to the actuation point. The firstcontact element 334 a and the second contact element are connected to,directly or through a relay, complete the circuit of the LED tube lamp.

In some embodiments, two end caps of the LED tube lamp according to theembodiments of the present invention may configure two micro switches,correspondingly. In this way, the hurt resulting from leaking current tothe user can be avoided when the LED tube lamp is in installation.

Turning to FIG. 40F, in accordance with an exemplary embodiment of thepresent invention, the end cap 3 includes a housing 300; a power supply(not shown); an electrically conductive pin 301 extending outwardly froma top wall of the housing 300; an actuator 332 movably connected to thehousing; a first contact element; and a second contact element. Theupper portion of the actuator 332 projects out of an opening formed inthe top wall of the housing 300. The actuator 332 includes, inside thehousing 300, a stopping flange extending radially from its intermediaryportion and a shaft 335 extending axially in its lower portion. Theshaft 335 is movably connected to a base rigidly mounted inside thehousing 300. A preloaded coil spring 333 is retained, around the shaft335, between the stopping flange and the base. The actuator 332 isaligned with the electrically conductive pin 301, the opening in the topwall of the housing 300, the coil spring 333, the first contact elementand the second contact element along the longitudinal axis of the lamptube to be reciprocally movable between the top wall of the housing 300and the base. The shaft 335 includes a non-electrically conductive bodyin the shape of an elongated thin plank and a window 339 carved out fromthe body. The first contact element and the second contact element arefixedly disposed inside the housing 300 and face each other through theshaft 335. The first contact element is configured to impart aspring-like bias on the shaft 335 and to urge the shaft 335 against thesecond contact element. In an embodiment, the first contact element is abow-shaped laminate bending towards the shaft 335 and the second contactelement, which is disposed on the power supply. The first contactelement and the second contact element are made from, for example,copper, copper alloy or both. When the actuator 332 is in its restposition, the first contact element and the second contact element areprevented by the body of the shaft 335 from engaging each other.However, the first contact element is configured to, when the shaftbrings its window 339 downwards to a predetermined actuation point,engage and electrically connect the second contact element through thewindow 339. When the electrically conductive pin 301 is unplugged fromthe socket, the coil spring 333 biases the actuator 332 to its restposition until the stopping flange is urged against the top wall of thehousing 300. The first contact element and the second contact elementstay unconnected and the circuit of the LED tube lamp stays open. Whenthe electrically conductive pin 301 is duly plugged into the socket on alamp holder, the actuator 332 is depressed and brings the window 339 tothe actuation point. The first contact element engages the secondcontact element to, directly or through a relay, complete the circuit ofthe LED tube lamp.

In some embodiments, two end caps of the LED tube lamp according to theembodiments of the present invention may configure two micro switches,correspondingly. In this way, the hurt resulting from leaking current tothe user can be avoided when the LED tube lamp is in installation.

In some embodiments, the upper portion of the actuator 332 that projectsout of the housing 300 is shorter than the electrically conductive pin301. In some embodiments, the ratio of the depth of the upper portion ofthe actuator 332 to that of the electrically conductive pin 301 is from20% to 95%.

In some embodiments, the length of the second side end cap 3 is shorterthan that of the first side end cap 3. In general, the length of thesecond side end cap 3 is about 30% to 80% times that of the first sideend cap 3, for example, the length of the second side end cap 3 is insome embodiments about ⅔ of the length of second side end cap 3. In thepresent embodiment, the length of the second side end cap 3 may be abouthalf the length of the first side end cap 3. The length of the firstside end cap 3 may be, e.g., in the range of about 15 mm to 65 mm,depending on practical situations.

It's worth noting that the thickness of the second conductive layer of atwo-layered bendable circuit sheet is, in some embodiments, larger thanthat of the first conductive layer in order to reduce the voltage dropor loss along each of the positive lengthwise portion and the negativelengthwise portion disposed in the second conductive layer. Compared toa one-layered bendable circuit sheet, since a positive lengthwiseportion and a negative lengthwise portion are disposed in a secondconductive layer in a two-layered bendable circuit sheet, the width(between two lengthwise sides) of the two-layered bendable circuit sheetis or can be reduced. On the same fixture or plate in a productionprocess, the number of bendable circuit sheets each with a shorter widththat can be laid together at most is larger than the number of bendablecircuit sheets each with a longer width that can be laid together atmost. Thus adopting a bendable circuit sheet with a shorter width canincrease the efficiency of production of the LED module. And reliabilityin the production process, such as the accuracy of welding position whenwelding (materials on) the LED components, can also be improved, becausea two-layered bendable circuit sheet can better maintain its shape.

As a variant of the above embodiments, a type of LED tube lamp isprovided that has at least some of the electronic components of itspower supply module disposed on a light strip of the LED tube lamp. Forexample, the technique of printed electronic circuit (PEC) can be usedto print, insert, or embed at least some of the electronic componentsonto the light strip.

In one embodiment, all electronic components of the power supply moduleare disposed on the light strip. The production process may include orproceed with the following steps: preparation of the circuit substrate(e.g. preparation of a flexible printed circuit board); ink jet printingof metallic nano-ink; ink jet printing of active and passive components(as of the power supply module); drying/sintering; ink jet printing ofinterlayer bumps; spraying of insulating ink; ink jet printing ofmetallic nano-ink; ink jet printing of active and passive components (tosequentially form the included layers); spraying of surface bond pad(s);and spraying of solder resist against LED components.

In certain embodiments, if all electronic components of the power supplymodule are disposed on the light strip, electrical connection betweenterminal pins of the LED tube lamp and the light strip may be achievedby connecting the pins to conductive lines which are welded with ends ofthe light strip. In this case, another substrate for supporting thepower supply module is not required, thereby allowing of an improveddesign or arrangement in the end cap(s) of the LED tube lamp. In someembodiments, (components of) the power supply module are disposed at twoends of the light strip, in order to significantly reduce the impact ofheat generated from the power supply module's operations on the LEDcomponents. Since no substrate other than the light strip is used tosupport the power supply module in this case, the total amount ofwelding or soldering can be significantly reduced, improving the generalreliability of the power supply module.

Another case is that some of all electronic components of the powersupply module, such as some resistors and/or smaller size capacitors,are printed onto the light strip, and some bigger size components, suchas some inductors and/or electrolytic capacitors, are disposed in theend cap(s). The production process of the light strip in this case maybe the same as that described above. And in this case disposing some ofall electronic components on the light strip is conducive to achieving areasonable layout of the power supply module in the LED tube lamp, whichmay allow of an improved design in the end cap(s).

As a variant embodiment of the above, electronic components of the powersupply module may be disposed on the light strip by a method ofembedding or inserting, e.g. by embedding the components onto a bendableor flexible light strip. In some embodiments, this embedding may berealized by a method using copper-clad laminates (CCL) for forming aresistor or capacitor; a method using ink related to silkscreenprinting; or a method of ink jet printing to embed passive components,wherein an ink jet printer is used to directly print inks to constitutepassive components and related functionalities to intended positions onthe light strip. Then through treatment by ultraviolet (UV) light ordrying/sintering, the light strip is formed where passive components areembedded. The electronic components embedded onto the light stripinclude, for example, resistors, capacitors, and inductors. In otherembodiments, active components also may be embedded. Through embeddingsome components onto the light strip, a reasonable layout of the powersupply module can be achieved to allow of an improved design in the endcap(s), because the surface area on a printed circuit board used forcarrying components of the power supply module is reduced or smaller,and as a result the size, weight, and thickness of the resulting printedcircuit board for carrying components of the power supply module is alsosmaller or reduced. Also in this situation, since welding points on theprinted circuit board for welding resistors and/or capacitors if theywere not to be disposed on the light strip are no longer used, thereliability of the power supply module is improved, in view of the factthat these welding points are most liable to (cause or incur) faults,malfunctions, or failures. Further, the length of conductive linesneeded for connecting components on the printed circuit board istherefore also reduced, which allows of a more compact layout ofcomponents on the printed circuit board and thus improving thefunctionalities of these components.

With reference to FIGS. 19 and 20, a short circuit board 253 includes afirst short circuit substrate and a second short circuit substraterespectively connected to two terminal portions of a long circuit sheet251, and the electronic components of the power supply module arerespectively disposed on the first short circuit substrate and thesecond short circuit substrate. The first short circuit substrate andthe second short circuit substrate may have roughly the same length, ordifferent lengths. In general, the first short circuit substrate (i.e.the right circuit substrate of short circuit board 253 in FIG. 19 andthe left circuit substrate of short circuit board 253 in FIG. 20) has alength that is about 30%-80% of the length of the second short circuitsubstrate (i.e. the left circuit substrate of short circuit board 253 inFIG. 19 and the right circuit substrate of short circuit board 253 inFIG. 20). In some embodiments, the length of the first short circuitsubstrate is about ⅓-⅔ of the length of the second short circuitsubstrate. For example, in one embodiment, the length of the first shortcircuit substrate may be about half the length of the second shortcircuit substrate. The length of the second short circuit substrate maybe, for example in the range of about 15 mm to about 65 mm, depending onactual application occasions. In certain embodiments, the first shortcircuit substrate is disposed in an end cap at an end of the LED tubelamp, and the second short circuit substrate is disposed in another endcap at the opposite end of the LED tube lamp.

In some embodiments, due to the external driving power, the length ofthe end caps are shortened. For ensuring the total length of the LEDtube lamp to conform to a standard for a fluorescent lamp, a length ofthe lamp tube is lengthened to compensate the shortened length of theend caps. Due to the lengthened length of the lamp tube, the LED lightstring is correspondingly lengthened. Therefore, the interval ofadjacent two LEDs disposed on the LED light string becomes greater underthe same illuminance requirement. The greater interval increases theheat dissipation of the LEDs and so the operation temperature of theLEDs is lowered and the life-span of the LED tube lamp is extended.

The LED tube lamps according to various different embodiments of thepresent invention are described as above. With respect to an entire LEDtube lamp, the features including “adopting the bendable circuit sheetas the LED light strip”, and “utilizing the circuit board assembly(including a long circuit sheet and a short circuit board) to connectthe LED light strip and the power supply” may be applied in practicesingly or integrally such that only one of the features is practiced ora number of the features are simultaneously practiced.

Furthermore, the feature “adopting the bendable circuit sheet as the LEDlight strip” includes any related technical points and their variationsand any combination thereof as described in the abovementionedembodiments of the present invention.

As an example, the feature “adopting the bendable circuit sheet as theLED light strip” includes “the connection between the bendable circuitsheet and the power supply is by way of wire bonding or solderingbonding; the bendable circuit sheet includes a wiring layer and adielectric layer arranged in a stacked manner; the bendable circuitsheet has a circuit protective layer made of ink to reflect lights andhas widened part along the circumferential direction of the lamp tube tofunction as a reflective film.”

For example, according to the design of the power supply in someembodiments, the circuit board assembly has a long circuit sheet and ashort circuit board that are adhered to each other with the shortcircuit board being adjacent to the side edge of the long circuit sheet.The short circuit board may be provided with power supply module to formthe power supply.

For the drive architecture of dual-end power supply, the externaldriving signal may be input by using only one end thereof as single-endpower supply.

The LED tube lamp may omit the rectifying circuit in the power supplymodule when the external driving signal is a DC signal.

According to the design of the rectifying circuit in the power supplymodule, there may be a signal rectifying circuit, or dual rectifyingcircuit. First and second rectifying circuits of the dual rectifyingcircuit are respectively coupled to the two end caps disposed on twoends of the LED tube lamp. The single rectifying circuit is applicableto the drive architecture of signal-end power supply, and the dualrectifying circuit is applicable to the drive architecture of dual-endpower supply. Furthermore, the LED tube lamp having at least onerectifying circuit is applicable to the drive architecture of lowfrequency AC signal, high frequency AC signal or DC signal.

According to the design of the pin in the LED tube lamp, there may betwo pins in single end (the other end has no pin), two pins incorresponding end of two ends, or four pins in corresponding end of twoends. The designs of two pins in single end and two pins incorresponding end of two ends are applicable to signal rectifyingcircuit design of the rectifying circuit. The design of four pins incorresponding end of two ends is applicable to dual rectifying circuitdesign of the rectifying circuit, and the external driving signal can bereceived by two pins in only one end or any pin in each of two ends.

A protection circuit may be additionally added to protect the LEDmodule. The protection circuit detects the current and/or the voltage ofthe LED module to determine whether to enable corresponding over currentand/or over voltage protection.

According to the design of the auxiliary power module of the powersupply module, the energy storage unit may be a battery or asupercapacitor, connected in parallel with the LED module. The auxiliarypower module is applicable to the LED lighting module having the drivingcircuit.

According to the design of the LED module of the power supply module,the LED module comprises plural strings of LEDs connected in parallelwith each other, wherein each LED may have a single LED chip or pluralLED chips emitting different spectrums. Each LEDs in different LEDstrings may be connected with each other to form a mesh connection.

The above-mentioned features of the present invention can beaccomplished in any combination to improve the LED tube lamp, and theabove embodiments are described by way of example only. The presentinvention is not herein limited, and many variations are possiblewithout departing from the spirit of the present invention and the scopeas defined in the appended claims.

What is claimed is:
 1. A light emitting diode (LED) tube lamp, comprising: a lamp tube; a first pin and a second pin coupled to a first end of the lamp tube, and a third pin coupled to a second end of the lamp tube; a first rectifying circuit comprising diodes and connected to the first and second pins, and a second rectifying circuit comprising diodes and connected to the third pin and an output terminal of the first rectifying circuit, wherein the first and second rectifying circuits are for rectifying an external driving signal to produce a rectified signal; a filtering circuit coupled to the two rectifying circuits and an LED module, for filtering the rectified signal to produce a filtered signal; an LED module comprising LEDs for emitting light, the LED module configured to be driven by the rectified signal or the filtered signal; and a driving circuit coupled between the two rectifying circuits and the LED module, and configured to drive the LED module, wherein the LED tube lamp is configured to receive the external driving signal and emit light in each of two power supply arrangements, the two arrangements being respectively that the external driving signal is a low frequency signal input and transmitted through the first and second pins, and that the external driving signal is a low frequency signal input and transmitted through one of the first and second pins and the third pin across the two ends of the lamp tube; wherein the LED tube lamp is configured such that when the received external driving signal is a low frequency signal, the LED tube lamp causes the rectified signal or the filtered signal to be used by the driving circuit for driving the LED module to emit light; and wherein the LED tube lamp is configured such that the driving circuit does not drive the LED module to emit light, when an external driving signal input through one of the first and second pins and the third pin across the two ends of the lamp tube is provided by an electrical ballast.
 2. The LED tube lamp according to claim 1, wherein the external driving signal as a low frequency signal is a signal having a frequency between 0 and 60 Hz.
 3. The LED tube lamp according to claim 1, wherein the external driving signal as a low frequency signal is from an AC powerline and not provided by an electrical ballast.
 4. The LED tube lamp according to claim 1, wherein the driving circuit comprises a DC-to-DC converter circuit configured for performing power conversion to produce a driving signal.
 5. The LED tube lamp according to claim 1, further comprising a mode switching circuit coupled to the two rectifying circuits and the driving circuit, and configured to cause the rectified signal or the filtered signal to be used by the driving circuit when the external driving signal is a low frequency signal.
 6. The LED tube lamp according to claim 1, further comprising an installation detection circuit coupled to the two rectifying circuits and the LED module, and configured such that when the LED tube lamp is properly connected to a lamp socket, the installation detection circuit conducts current or allows or causes the LED module to be driven by the rectified signal; and when the LED tube lamp is not properly connected to a lamp socket, the installation detection circuit prevents the LED module from being driven by the rectified signal.
 7. The LED tube lamp according to claim 6, wherein the installation detection circuit is configured for protecting a user from electric shock when the user is touching or inserting the LED tube lamp into a lamp socket.
 8. The LED tube lamp according to claim 1, wherein the first end of the lamp tube has an end cap on which the first and second pins are disposed, and the second end of the lamp tube has an end cap on which the third pin is disposed.
 9. The LED tube lamp according to claim 8, further comprising an installation detection mechanism providing electric shock protection, coupled to at least one of the two end caps, and comprising an actuator configured to move toward and extend away from the lamp tube.
 10. The LED tube lamp according to claim 9, wherein the installation detection mechanism further comprises a micro switch configured to be triggered by the actuator being pressed when the LED tube lamp is being touched or installed into a lamp socket, wherein the micro switch when triggered completes a circuit between at least one of the first and second rectifying circuits and at least one of the first, second, and third pins.
 11. The LED tube lamp according to claim 9, wherein the installation detection mechanism further comprises a first contact element and a second contact element configured to be triggered by the actuator being pressed when the LED tube lamp is being touched or installed into a lamp socket, wherein the first contact element is configured to engage the second contact element to complete a circuit between at least one of the first and second rectifying circuits and at least one of the first, second, and third pins when the first contact element and the second contact element are triggered by the actuator.
 12. The LED tube lamp according to claim 1, further comprising a safety switch coupled between at least one of the first and second rectifying circuits and at least one of the first, second, and third pins.
 13. The LED tube lamp according to claim 12, wherein the safety switch comprises an electric switch, a thyristor, or a logic level switch.
 14. The LED tube lamp according to claim 12, further comprising a capacitor or resistor connected in parallel with the safety switch and between at least one of the first and second rectifying circuits and at least one of the first, second, and third pins.
 15. The LED tube lamp according to claim 14, wherein the capacitor or resistor constitutes a filtering unit.
 16. The LED tube lamp according to claim 1, wherein the first rectifying circuit comprises four diodes, the first pin is connected to a common node connecting an anode and a cathode respectively of two of the four diodes, and the second pin is connected to a common node connecting an anode and a cathode respectively of the other two of the four diodes.
 17. The LED tube lamp according to claim 1, wherein the second rectifying circuit comprises two diodes having a common node connecting an anode and a cathode respectively of the two diodes, and one of the two diodes has another terminal connected to the third pin.
 18. The LED tube lamp according to claim 1, wherein the second rectifying circuit comprises two diodes having a common node connecting an anode and a cathode respectively of the two diodes, and the common node is coupled to the third pin.
 19. The LED tube lamp according to claim 1, wherein the second rectifying circuit comprises four diodes, and the third pin is connected to a common node connecting an anode and a cathode respectively of two of the four diodes.
 20. The LED tube lamp according to claim 1, wherein the first rectifying circuit comprises four diodes, the first pin is connected to a first common node connecting an anode and a cathode respectively of two of the four diodes, and the second pin is connected to a second common node connecting an anode and a cathode respectively of the other two of the four diodes; the second rectifying circuit comprises two diodes having a third common node connecting an anode and a cathode respectively of the two diodes of the second rectifying circuit, and the third common node is coupled to the third pin; and a common anode of two of the four diodes of the first rectifying circuit is coupled to an anode of one of the two diodes of the second rectifying circuit, and a common cathode of the other two of the four diodes of the first rectifying circuit is coupled to a cathode of the other one of the two diodes of the second rectifying circuit.
 21. A light emitting diode (LED) tube lamp, comprising: a lamp tube; a first pin and a second pin coupled to a first end of the lamp tube, and a third pin coupled to a second end of the lamp tube; a first rectifying circuit comprising diodes and connected to the first and second pins, and a second rectifying circuit comprising diodes and connected to the third pin and an output terminal of the first rectifying circuit, wherein the first and second rectifying circuits are for rectifying an external driving signal to produce a rectified signal; a filtering circuit coupled to the two rectifying circuits and an LED module, for filtering the rectified signal to produce a filtered signal; an LED module comprising LEDs for emitting light, the LED module configured to be driven by the rectified signal or the filtered signal; a driving circuit coupled between the two rectifying circuits and the LED module, and configured to drive the LED module; and a detection module coupled to the two rectifying circuits for protecting a user from electric shock, having two detection terminals, and configured to not conduct current between the two detection terminals when the external driving signal is input at the first and second pins, wherein the LED tube lamp is configured to receive an external driving signal in a power supply arrangement in which the external driving signal is input and transmitted through the third pin and one of the first and second pins across the two ends of the lamp tube; wherein the detection module includes a switch circuit coupled between the two detection terminals, configured to be in a conducting state when the LED tube lamp receives an external driving signal input and transmitted through the third pin and one of the first and second pins across the two ends of the lamp tube; and wherein the switch circuit is connected between the third pin and one of the first and second pins; the second rectifying circuit comprises two serially-connected diodes, and a common node between the two diodes is connected to the third pin and a first terminal of the switch circuit; and the first rectifying circuit comprises two other serially-connected diodes, and a common node between the two other diodes is connected to both a second terminal of the switch circuit and the first or second pin.
 22. The LED tube lamp according to claim 21, further comprising a conduction-delaying circuit coupled to the two rectifying circuits, the filtering circuit, and the LED module, wherein the conduction-delaying circuit is configured such that when the external driving signal is initially input to the LED tube lamp, the conduction-delaying circuit is in an open-circuit state, and then the conduction-delaying circuit enters a conducting state when voltage across the conduction-delaying circuit exceeds a trigger voltage value of the conduction-delaying circuit, wherein the conducting state of the conduction-delaying circuit causes the LED module to conduct current for emitting light.
 23. The LED tube lamp according to claim 22, wherein the conduction-delaying circuit comprises a ballast-compatible circuit comprising an electronic switch and a capacitor; the electronic switch is connected between a first and a second terminals of the ballast-compatible circuit and has a control terminal coupled to the capacitor; and the ballast-compatible circuit is configured such that when an external driving signal is initially input to the LED tube lamp, the electronic switch is in an open-circuit state, and the capacitor is then charged so as to trigger the electronic switch into a conducting state, making the ballast-compatible circuit enter the conduction state.
 24. The LED tube lamp according to claim 23, wherein the electronic switch comprises a thyristor.
 25. The LED tube lamp according to claim 23, wherein the ballast-compatible circuit further comprises a resistor connected between the first terminal of the ballast-compatible circuit and the control terminal of the electronic switch, and another resistor connected between the second terminal of the ballast-compatible circuit and the control terminal of the electronic switch.
 26. The LED tube lamp according to claim 21, wherein the external driving signal input at the first and second pins is a signal from an AC powerline.
 27. The LED tube lamp according to claim 21, wherein in the power supply arrangement the external driving signal is a signal from an electrical ballast.
 28. The LED tube lamp according to claim 21, wherein the switch circuit is configured to be in the conducting state to make the detection module conduct current, and configured to be in a cut-off state to make the LED tube lamp enter in a non-conducting state.
 29. The LED tube lamp according to claim 21, further comprising an impedance circuit coupled between the first and second pins and the first rectifying circuit, or between the third pin and the second rectifying circuit, for reducing EMI (electromagnetic interference), limiting electrical current, or providing overcurrent protection.
 30. The LED tube lamp according to claim 29, wherein the impedance circuit comprises a resistor, a capacitor, an inductor, or any combination thereof.
 31. The LED tube lamp according to claim 29, wherein the impedance circuit comprises a fuse connected to at least one of the first, second, and third pins.
 32. The LED tube lamp according to claim 21, wherein the detection module is configured to not conduct current between the two detection terminals when the first end of the LED tube lamp is inserted into a lamp socket and the second end of the LED tube lamp floats or couples to an object.
 33. The LED tube lamp according to claim 21, wherein the LED tube lamp is configured such that when the external driving signal is a low frequency signal input and transmitted through the third pin and one of the first and second pins across the two ends of the lamp tube, the LED tube lamp causes the rectified signal or the filtered signal to be used by the driving circuit for driving the LED module to emit light.
 34. A light emitting diode (LED) tube lamp, comprising: a lamp tube; a first pin and a second pin coupled to a first end of the lamp tube, and a third pin coupled to a second end of the lamp tube; a first rectifying circuit comprising diodes and connected to the first and second pins, and a second rectifying circuit comprising diodes and connected to the third pin and an output terminal of the first rectifying circuit, wherein the first and second rectifying circuits are for rectifying an external driving signal to produce a rectified signal; a filtering circuit coupled to the two rectifying circuits and an LED module, for filtering the rectified signal to produce a filtered signal; an LED module comprising LEDs for emitting light, the LED module configured to be driven by the rectified signal or the filtered signal; and a driving circuit coupled between the two rectifying circuits and the LED module, and configured to drive the LED module, wherein the LED tube lamp is configured to receive the external driving signal and emit light in each of two power supply arrangements, the two arrangements being respectively that the external driving signal is a signal having a frequency between 40 and 60 Hz input and transmitted through the first and second pins, and that the external driving signal is a signal having a frequency between 40 and 60 Hz input and transmitted through one of the first and second pins and the third pin across the two ends of the lamp tube; wherein the LED tube lamp is configured such that when the received external driving signal is a signal having a frequency between 40 and 60 Hz, the LED tube lamp causes the rectified signal or the filtered signal to be used by the driving circuit for driving the LED module to emit light, and wherein the LED tube lamp is configured such that the driving circuit does not drive the LED module to emit light, when an external driving signal input through one of the first and second pins and the third pin across the two ends of the lamp tube is provided by an electrical ballast.
 35. The LED tube lamp according to claim 34, wherein the driving circuit comprises a DC-to-DC converter circuit configured for performing power conversion to produce a driving signal.
 36. The LED tube lamp according to claim 34, further comprising a mode switching circuit coupled to the two rectifying circuits and the driving circuit, and configured to cause the rectified signal or the filtered signal to be used by the driving circuit when the external driving signal is a low frequency signal.
 37. The LED tube lamp according to claim 34, further comprising an installation detection circuit coupled to the two rectifying circuits and the LED module, and configured such that when the LED tube lamp is properly connected to a lamp socket, the installation detection circuit conducts current or allows the LED module to be driven by the rectified signal; and when the LED tube lamp is not properly connected to a lamp socket, the installation detection circuit prevents the LED module from being driven by the rectified signal.
 38. The LED tube lamp according to claim 34, further comprising a safety switch coupled between at least one of the first and second rectifying circuits and at least one of the first, second, and third pins.
 39. The LED tube lamp according to claim 38, further comprising a capacitor or resistor connected in parallel with the safety switch and between at least one of the first and second rectifying circuits and at least one of the first, second, and third pins.
 40. A light emitting diode (LED) tube lamp, comprising: a lamp tube; a first pin and a second pin coupled to a first end of the lamp tube, and a third pin coupled to a second end of the lamp tube; a first rectifying circuit comprising diodes and connected to the first and second pins, and a second rectifying circuit comprising diodes and connected to the third pin and an output terminal of the first rectifying circuit, wherein the first and second rectifying circuits are for rectifying an external driving signal to produce a rectified signal; a filtering circuit coupled to the two rectifying circuits and an LED module, for filtering the rectified signal to produce a filtered signal; an LED module comprising LEDs for emitting light, the LED module configured to be driven by the rectified signal or the filtered signal; a driving circuit coupled between the two rectifying circuits and the LED module, and configured to drive the LED module; and a detection module coupled to the two rectifying circuits for protecting a user from electric shock, having two detection terminals, and configured to not conduct current between the two detection terminals when the external driving signal is input at the first and second pins, wherein the detection module includes a switch circuit coupled between the two detection terminals and configured to be in a conducting state when the LED tube lamp receives an external driving signal input and transmitted through the third pin and one of the first and second pins across the two ends of the lamp tube, wherein the LED tube lamp is configured to receive an external driving signal in a power supply arrangement in which the external driving signal is input and transmitted through the third pin and one of the first and second pins across the two ends of the lamp tube; the LED tube lamp further comprising a ballast-compatible circuit connected between the third pin and one of the first and second pins, wherein the ballast-compatible circuit comprises the switch circuit, and the switch circuit is configured to be in a conducting state when the LED tube lamp receives an external driving signal from an electrical ballast; and upon the LED tube lamp receiving an external driving signal from an electrical ballast, the switch circuit initially conducts current bypassing the LED module and between the third pin and one of the first and second pins, causing then a current to flow between the third pin and one of the first and second pins through the first and second rectifying circuits, the driving circuit, and the LED module for emitting light.
 41. The LED tube lamp according to claim 40, wherein the ballast-compatible circuit is coupled to an output terminal of the first rectifying circuit or the second rectifying circuit.
 42. The LED tube lamp according to claim 40, wherein the switch circuit comprises a transistor connected between two terminals of the ballast-compatible circuit.
 43. The LED tube lamp according to claim 21, further comprising a capacitor having one end connected to the third pin or the common node between the two diodes of the second rectifying circuit, and another end connected to the first terminal of the switch circuit.
 44. The LED tube lamp according to claim 21, further comprising a capacitor having one end connected to the first pin or the common node between the two diodes of the first rectifying circuit, and another end connected to the second terminal of the switch circuit.
 45. The LED tube lamp according to claim 21, wherein the first or second rectifying circuit includes a rectifying unit and a terminal adapter circuit; the rectifying unit comprises the two serially-connected diodes of the respective first or second rectifying circuit; and the terminal adapter circuit is connected to the common node between the two serially-connected diodes of the respective first or second rectifying circuit.
 46. The LED tube lamp according to claim 1, wherein the electrical ballast comprises an electronic ballast.
 47. The LED tube lamp according to claim 1, wherein the external driving signal provided by an electrical ballast has a frequency in the range of 10 k - 50 k Hz.
 48. The LED tube lamp according to claim 1, wherein when the external driving signal provided by an electrical ballast is input across the two ends of the lamp tube, the rectified signal or the filtered signal bypasses at least a component of the driving circuit, and then drives the LED module to emit light.
 49. The LED tube lamp according to claim 6, wherein the installation detection circuit includes a switch circuit coupled between two detection terminals of the installation detection circuit, configured to be in a conducting state to make the installation detection circuit conduct current, and configured to be in a cut-off state to make the LED tube lamp enter in a non-conducting state.
 50. The LED tube lamp according to claim 21, wherein the first rectifying circuit consists of four diodes, the first pin is connected to a first common node connecting an anode and a cathode respectively of two of the four diodes, and the second pin is connected to a second common node connecting an anode and a cathode respectively of the other two of the four diodes; the second rectifying circuit consists of two diodes having a third common node connecting an anode and a cathode respectively of the two diodes of the second rectifying circuit, and the third common node is coupled to the third pin; and a common anode of two of the four diodes of the first rectifying circuit is coupled to an anode of one of the two diodes of the second rectifying circuit, and a common cathode of the other two of the four diodes of the first rectifying circuit is coupled to a cathode of the other one of the two diodes of the second rectifying circuit.
 51. The LED tube lamp according to claim 34, wherein the first rectifying circuit consists of four diodes, the first pin is connected to a first common node connecting an anode and a cathode respectively of two of the four diodes, and the second pin is connected to a second common node connecting an anode and a cathode respectively of the other two of the four diodes; the second rectifying circuit consists of two diodes having a third common node connecting an anode and a cathode respectively of the two diodes of the second rectifying circuit, and the third common node is coupled to the third pin; and a common anode of two of the four diodes of the first rectifying circuit is coupled to an anode of one of the two diodes of the second rectifying circuit, and a common cathode of the other two of the four diodes of the first rectifying circuit is coupled to a cathode of the other one of the two diodes of the second rectifying circuit. 